On the Scale of Global Demographic Convergence 1950-2000Author(s): Chris WilsonSource: Population and Development Review, Vol. 27, No. 1 (Mar., 2001), pp. 155-171Published by: Population CouncilStable URL: http://www.jstor.org/stable/2695158 .Accessed: 17/02/2011 12:53

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DATA AND PERSPECTIVES

On the Scale of Global Demographic Convergence 1950-2000

CHRIS WILSON

THE SECOND HALF of the twentieth century saw global demographic change of unprecedented magnitude. Taking the population of the world as a whole, the United Nations Population Division estimates that life expectancy at birth rose from 46.5 years in the early 1950s to 65.4 by the late 1990s (United Nations 1999: 8). Similarly, fertility fell from a global average of 5.0 chil- dren per woman to 2.7 over the same time scale. The purpose of this as- sessment is to see how far these changes have led to the convergence of demographic patterns around the world. In order to do so, I take into ac- count not just the levels of fertility and mortality in each country at differ- ent points in time, but also the size of each population. I also disaggregate China and India into their constituent provinces and states in order to pro- vide estimates for units more typical of the size of the populations of other countries. The assessment thus follows the lead of McNicoll (1999) in con- sidering population weights, rather than nations, as its main focus. It pre- sents proportions of the world's population according to the levels of life expectancy and total fertility they experience. The graphs and tables thus produced represent a convenient and novel way to view the scale and na- ture of demographic convergence over the last 50 years.

The concept of convergence lies at the heart of demographic transi- tion theory. However, as Oeppen (1999: 11) puts it, 'Despite this, there seems to have been no attempt to address convergence in a formal way." This is in marked contrast with economics, where quantitative assessments of convergence form a central part of modern economic growth theory (Barro and Sala-i-Martin 1999; Landau, Taylor, and Wright 1996). Oeppen's work on life expectancy and that of Chesnais (1997) are among the few attempts to deal with convergence explicitly, while Heuveline (1999) considers the

POPULATION AND DEVELOPMENT REVIEW 27(1):155-171 (MARCH 2001) 155

156 GLOBAL DEMOGRAPHIC CONVERGENCE

consequences of convergence on a regional and global scale. Here I do not at- tempt to advance the methodological agenda, but rather focus on establishing the scale and nature of the convergence of demographic phenomena.

Data

Of all the data collection and production tasks carried out by the various organizations of the United Nations, none is more helpful to a demogra- pher seeking to assess long-term trends than the regularly revised World Population Prospects (United Nations 1999). For almost every member state of the United Nations (only countries with tiny populations are treated sepa- rately) and a number of other territories (184 entities in all in the 1998 revision), that publication gives detailed demographic estimates from 1950 on, and it makes projections for future populations. The validity and utility of the projections as a forecasting tool can be debated (National Research Council 2000), but the value of the comprehensive estimates of demographic variables for virtually all nations and territories over the last 50 years is beyond dispute. The inherently egalitarian nature of the process (at the na- tional level) is exemplified by the fact that all states and territories receive equal treatment in the main tables. Iceland (with a population of 268,000 in 2000) occupies the same space, and on the immediately preceding pages, as India (where the population exceeds one billion). This provides a level of coverage of demographic estimates that has few, if any, parallels in other aspects of social or economic life. The most recent version of the World Popu- lation Prospects, the 1998 revision, is used as the basis for most of the results presented below.

As any scholar who has examined the World Population Prospects soon realizes, however, the quality and extent of the basic information from which the UN's demographers derive their estimates are highly variable. For most of Europe, North America, Australasia, and Japan abundant and adequate resources in the form of census and vital registration data are available for the whole period since 1950. The situation in much of the rest of the world is less favorable. Almost all developing countries have incomplete census or survey data for the early decades under consideration, and a large fraction still lack fully complete vital registration. The lack of data reaches extreme levels for very poor countries that have also suffered from extended inter- nal conflicts, such as Angola and Afghanistan. Even though a good deal of the basic statistical input remains problematic, the authors of the World Popu- lation Prospects manage to produce internally consistent and plausible esti- mates for all countries from 1950 on. Scholars may debate the accuracy of many of the specific estimates, but the broad patterns in the levels and trends of fertility, mortality, and population growth are almost certainly beyond dispute. In any event, many of the assumptions and estimates for the earli-

CHRIS WILSON 157

est dates, for which the greatest uncertainty exists, are unlikely ever to be subject to serious challenge, as the absence of primary data means that the true situation will never be known. Thus, in the large majority of cases, the UN's estimates are probably the best available figures for the earlier decades under consideration.

When dealing with more recent estimates, there is a possibility that so large an enterprise as the World Population Prospects may lead to some tardi- ness in revising estimates according to rapidly changing circumstances. Ex- amination of national estimates does indeed suggest a certain homogeniz- ing tendency, in which the diversity of individual country experience is somewhat muted. For example, the full impact of the HIV/AIDS epidemic in southern Africa is probably not reflected in the estimates for the late 1 990s. Similarly, earlier revisions of the estimates seem to have been slow in inte- grating very rapid declines in fertility, such as that seen in Iran since the mid-1980s. Nevertheless, the overall picture that emerges from the UN's work is very similar to estimates made by other organizations. For example, the Population Reference Bureau (PRB) draws on a variety of sources, but especially on the work of the U.S. Census Bureau's International Division, in making its estimates of current demographic trends. When comparing estimates of total fertility for the year 2000 made by the UN and the PRB, there is a difference of less than 0.2 children per woman in the weighted average of all nations; life expectancy differs by less than a year in the UN and PRB estimates (Population Reference Bureau 2000).

Within this general picture, two countries deserve special attention. The sheer scale of the populations of China and India intrudes into any attempt to summarize the state of the world's population. In 1950 China's 555 million inhabitants represented 22 percent of humanity, while India's 358 million made up 14 percent. In 2000 these demographic giants repre- sented 21 percent and 17 percent. Any consideration of cumulative popu- lation, as presented here, becomes unavoidably discontinuous if India and China are retained as single entities. Graphs of the kind presented below, in Figures 1 and 3 for example, take on a "~step pyramid" appearance. Fortu- nately the two behemoths are among the better-documented parts of the developing world. Thus it is possible, with only modest recourse to assump- tion and interpolation, to assess the demographic characteristics of China's provinces and India's states for much of the last 50 years. The Registrar General of India provides data on the main states of India throughout this period, and fertility surveys are relatively abundant for the 1 980s and 1 990s. In addition, a number of scholars, mostly notably Bhat, Preston, and Dyson (1984), have analyzed the official data in order to extract the most plau- sible estimates for the larger states before the 1980s. These secondary sources can provide reasonably solid estimates of both total fertility and life expect- ancy for periods in which the official data are scanty. Data on China's prov-

158 GLOBAL DEMOGRAPHIC CONVERGENCE

inces are also fairly solid and readily available. For fertility Coale and Chen (1987) provide a province-level analysis of the results of the 1982 One-per- Thousand survey, while recent official statistics and Chinese secondary sources can fill in the period since then. Chinese mortality is less well docu- mented, especially during the 1950s, but sufficient data are available even for that time to permit a plausible decomposition of national trends. Taking a broader perspective, compared with the heroic scale of the assumptions that underlie the UN estimates for some developing countries, the extent to which we need to interpolate or adjust the Indian and Chinese data in or- der to obtain subnational estimates is modest. Details of the sources and assumptions used to estimate the subnational information used in this as- sessment are given in the Appendix.

Although the approach taken here, of treating the states of India and the provinces of China as equivalent to nations, is not conventional, it does have merit. First, both countries have a good deal of regional variation in their demographic characteristics that is lost when a strictly national per- spective is taken. Moreover, the resultant entities are scarcely small. For example, if the Indian state of Uttar Pradesh were an independent nation, it would today be the fourth most populous on Earth (assuming China and India are disaggregated), with more inhabitants than Pakistan or Russia. China's most populous province for the last half-century, Sichuan, has re- cently been divided into two, but using the definition that applied from 1950 to 1997 it is home to more than 120 million people. This would be the ninth largest population in the world, substantially larger than Nigeria, for example. In fact, in the data arrangement used here, 13 of the 25 most populous entities are located within India or China. Similarly, of the 50 largest populations, 25 are subdivisions of the two giants. All in all, the sub- divisions of India and China are in many respects readily comparable with other nations. One result of taking this disaggregating approach is that no individual entity constitutes a particularly large fraction of the world's total population. The United States is the largest entity, constituting 6.3 percent of the world total in 1950 and 4.6 percent in 2000.

Results

Figures 1 and 3 plot, respectively, the changes over time in total fertility and in life expectancy at birth for the global population. Each figure pre- sents cumulative proportions of the world's population experiencing given levels of fertility and mortality. The graphs are arranged so that trends over the demographic transition tend to move populations from left to right across the figures. For fertility this involves plotting the results on a reversed scale. Thus, Figure 1 plots the proportion of the population living in countries or regions in which total fertility exceeds a given level. Figure 3 shows how many

CHRIS WILSON 159

FIGURE 1 Cumulative distribution of the global population by total fertility, 1950-55, 1975-80, and 2000

100

I75 . . .... . ................. . _............. . .................. . .... ......... .... . ..... . . .........

1950-55

1975-80

50

7~ 2000 ; ~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~- - - - 2 5 . . . .......... . ..;_

0 9 8 7 6 5 4 3 2

Total fertility SOURCES: See Appendix.

people live in places in which life expectancy is less than a given level. The results are plotted for 1950-55, 1975-80, and 2000. Each figure also shows horizontal lines representing the median and upper and lower quartiles of the world's population. Tables 1 and 3 investigate the cumulative distributions fur- ther, giving the 10th, 2 5th, 50th, 7 5th, and 90th percentiles.

To flesh out the details of change, Figures 2 and 4 present the same information in the form of histograms, while Tables 2 and 4 provide the

TABLE 1 Total fertility rates at the 10th, 25th, 50th, 75th, and 90th percentiles of the cumulative fertility distribution: World population 1950-55, 1975-80, and 2000

Percentile 1950-55 1975-80 2000

10th 6.74 6.66 4.83 25th 6.15 5.32 3.20 50th 5.40 3.64 2.28 75th 3.45 2.13 1.74 90th 2.51 1.79 1.39

SOURCES: See Appendix.

FIGURE 2 Percent of global population at each fertility level by type of country, 1950-55, 1975-80, and 2000

25 1950-55

5 Developing U Communist El Developed .? 20 -

n;15_ .0 0

O 0 10

04

0 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0

Total fertility

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NOTE: See text for definitions of country categories. SOURCES: See Appendix.

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162 GLOBAL DEMOGRAPHIC CONVERGENCE

FIGURE 3 Cumulative distribution of the global population by life expectancy at birth, 1950-55, 1975-80, and 2000

100

B 7 i . X. X................................................................................................... ................................

1950-55

1975-80

2000

2 5 -- -- - ------; -_ ------ -

0 30 40 50 60 70 80

Life expectancy at birth

SOURCES: See Appendix.

data that are plotted there. These tables and figures also distinguish between developed and developing countries and the former Communist states of the Soviet Union and Eastern Europe. Any definition of developed and de- veloping nations is in some degree arbitrary. However, the fundamental differences in the respective histories of the First, Second, and Third Worlds over the last 50 years justify the trichotomy. In this assessment 'Communist" is defined as the Soviet Union and all European countries ruled by Communist parties in the Cold War era. The "developed" category includes the other Euro-

TABLE 3 Life expectancy at birth at the 10th, 25th, 50th, 75th, and 90th percentiles of the cumulative mortality distribution: World population 1950-55, 1975-80, and 2000

Percentile 1950-55 1975-80 2000

10th 34.3 47.0 54.3 25th 37.7 53.4 64.5 50th 44.8 62.5 68.1 75th 64.3 69.3 72.5 90th 69.0 73.2 77.1

SOURCES: See Appendix.

FIGURE 4 Percent of global population at each level of life expectancy at birth, by type of country, 1950-55, 1975-80, and 2000

1950-55

F 30 Developing U Communist EJ Developed 0

25 -

0 ?20- 10

0

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NOTE: See text for definitions of country categories. SOURCES: See Appendix.

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CHRIS WILSON 165

pean countries (excluding Turkey), along with the United States, Canada, Aus- tralia, New Zealand, and Japan. "Developing" is the rest of the world.

Fertility

The change over time in fertility is striking, with the curves in Figure 1 shifting from a convex to a concave pattern. The line for 1950-55 rises rap- idly at high levels of fertility, indicating that large proportions of the world's population experienced these conditions. At that time, the median human lived in a country or region where total fertility was 5.4 children. After this initial rise, the 1950s curve flattens off, with relatively few populations hav- ing fertility in the range of 3.5 to 5.0 children per woman. The line rises again to the left, as the populations of the more developed countries enter the cumulation. In short, as Figure 2 makes clear, in the early 1950s there were two distinct fertility regimes: developed and developing. To the right- hand end of the figures are most of the populations of Europe, North America, and Australasia, with total fertility below 3.5. To the left-hand end, the major- ity of the world's population lived in developing countries with high fertility. Few people lived in places where fertility fell between these two regimes.

By the late 1970s, change was already substantial. By then the popu- lations of the world were located along an almost linear gradient in terms of fertility, and the median individual lived where total fertility was 3.6. After another two decades of demographic transition, the graphs for 2000 delineate a world that has been transformed. Today the median individual lives in a country or region in which total fertility is 2.3. Given the extent to which fertility has been declining in almost all countries, it is highly likely that by 2010 a majority of the world's people will live in places where fer- tility is below the level of long-run replacement, quite possibly by as early as 2005. In these countries and regions the only significant population growth to be expected in the course of demographic transition is that occa- sioned by demographic momentum (Bongaarts and Bulatao 1999). Also notice that the right-hand end of the fertility distribution has moved from a TFR of almost exactly 2 to little above 1. In only one country was total fertility below 2 in 1950 (Luxembourg at 1.98), whereas in 2000 almost 40 percent of humanity lived where the TFR was below 2.

A numerical indication of the extent of convergence is given in Table 1. In the early 1950s almost no country had fertility below the replacement level; the 90th percentile was 2.5, and the upper quartile almost 3.5. As mentioned above, the median value in 1950-5 5 was 5.4 children per woman, while more than a quarter of the world's population lived in places where the TFR exceeded 6. By 2000 the situation had been radically altered. The median is now close to the replacement level and the lower quartile (3.2) is actually below the value for the upper quartile half a century earlier. Only

166 GLOBAL DEMOGRAPHIC CONVERGENCE

10 percent of people live in areas where the TFR is above 4.8, compared with 63 percent in the early 1950s.

Another aspect of the situation in 2000 is evident only when examin- ing the constituent populations of the smooth curves in Figure 1. Today it is difficult to distinguish between developed and developing countries in terms of their fertility, and many developing-country populations are inter- mingled with the developed nations at the right-hand end of the figures. For example, fertility in the Indian states of Kerala and Tamil Nadu, as well in such countries as Sri Lanka and Thailand and much of China, is probably below that in the United States. In short, we are moving into a world where the distinction between developed and developing countries is of greatly diminished relevance to fertility. While no developed country is to be found in the left-hand tail of the distribution, the overwhelming trend is for low fertility to become a general feature of poor and rich countries alike.

While the main conclusion to be drawn from this exercise is that con- vergence in fertility is substantial, even in 2000 a significant tail of high- fertility populations remains to the left of the graph. Similarly, Table 1 indi- cates that the value for the 10th percentile has declined by a smaller proportion than the higher percentiles. In other words, while most of the developing world has moved rapidly toward convergence with the devel- oped world, a significant minority remains with much higher fertility. In fact, roughly 1.4 billion people live in countries or regions where total fer- tility is 3.5 or higher. A regional breakdown of this 1.4 billion is revealing. By far the largest contributions to this group come from sub-Saharan Africa and from northern parts of the Indian subcontinent. Both regions contrib- ute more than 550 million to the population with a total fertility of 3.5 and above, with smaller contributions from a few countries in Latin America, West Asia, Southeast Asia, and the Pacific. Although comprising less than a quarter of the world's population, the remaining high-fertility regions will, in any of the UN's future scenarios, provide the majority of the population growth expected for the next 50 years. It is not surprising, therefore, that addressing the reproductive health needs of these segments of the world's population remains of the highest priority for international population policy. On the other hand, today's definition of high fertility indicates the scale of change: 3.5 children per woman was scarcely regarded as "high" fertility in the early 1950s, when only 25 percent of the world's population had a TFR below this level.

Mortality

Figures 3 and 4 and Tables 3 and 4 repeat the data summary for life expect- ancy. As they indicate, mortality levels have shown even more remarkable convergence than fertility, with the change being especially marked between

CHRIS WILSON 167

1950-55 and 1975-80. In the early 1950s the dichotomy between devel- oped and developing countries was stark. The median individual lived where life expectancy was below 45 years, and very few people lived in countries or regions where this measure fell between 50 and 60. The gap between the median and the upper quartile was almost 20 years, and the inter-quar- tile range was 26. The transformation by the late 1970s was pronounced. The median had increased by almost 18 years to 63, while the inter-quar- tile range had dropped to 16 years. By 2000 the median individual experi- enced a life expectancy of 68, with a gap of just eight years between the quartiles.

As with fertility, an increasing overlap is found between the mortality of developed and developing countries. For example, life expectancy in much of East and Southeast Asia and Latin America is now higher than in many of the formerly Communist countries of Eastern Europe and the former Soviet Union. However, there remains a significant minority of the world's population for whom mortality improvement has been modest. Today a little under 20 percent of the population lives in countries or regions where life expectancy is below 60 years, and a ten-year gap remains between the 10th and 25th percentiles. Within this disadvantaged group, the ranking of indi- vidual countries in terms of life expectancy indicates the extent to which the lowest values have become concentrated in sub-Saharan Africa. In 2000 some 11 percent of the world's population, 650 million people, lived in coun- tries where life expectancy was 56 or less. This group includes almost every country in sub-Saharan Africa and only five countries elsewhere: Afghani- stan, Cambodia, East Timor, Haiti, and Laos.

A further point to bear in mind is that general progress toward longer life expectancy does not imply the absence of reversals. For example, be- tween 1975-80 and 2000 several countries in southern Africa saw life ex- pectancy decline substantially following the spread of HIV/AIDS. Similarly in Russia and several other countries in the former Soviet Union and East- ern Europe, life expectancy stagnated or declined over the same period, for reasons that are still subject to debate.

Conclusion

This has been a brief and simplified consideration of demographic conver- gence in the second half of the twentieth century; many of the points raised clearly merit a more extended evaluation. Nevertheless, it is hoped that the stylized presentation has illuminated the scale and nature of the phenom- enon. If we consider demographic transition in the light of broader mod- ernization theory, it is clear that social and demographic change has pro- gressed far more rapidly than economic development. A large majority of the world's population is (or soon will be) demographically "modern" by

168 GLOBAL DEMOGRAPHIC CONVERGENCE

any definition. It will be a long time, though, before a majority will be rich. Indeed, the title of a review of long-run change in income per head (Pritchett 1997) suggests that economic trends are best described as displaying "diver- gence, big time." In contrast with the enduring economic gulf between rich and poor countries (Maddison 1995), many aspects of the social agenda of development, particularly education, have shown a considerable narrow- ing of the gap between developed and developing countries. The demo- graphic convergence outlined here can, perhaps, be seen as one aspect of that increasing social similarity. By contrast, a comparison of the demo- graphic changes outlined in this assessment with trends in literacy (UNDP 1999) and urbanization (UN 1995) indicates that those aspects of develop- ment have shown slower rates of convergence than mortality and fertility.

In sum, while huge economic gaps remain between rich and poor coun- tries, we are moving into a world in which that distinction is of diminishing demographic relevance. A final set of simple comparisons can illustrate this observation. In 2000 total fertility in the United States was 2.1, compared with a global median of 2.3. For life expectancy the US value was 76 and the global median 68. By contrast, GNP per head in 1998, calculated on a purchasing-power-parity basis, was $30,600 for the United States, while the global median was $3,030 (World Bank 2000; India 1998; Liu et al. 1996).

Appendix: Data organization

Demographic series

Estimates of total fertility and life expectancy in the United Nations' publication World Population Prospects: The 1998 Revision form the basis of the results presented here (United Nations 1999). For all countries and territories given in that volume, except for China and India, this is the sole source of data. The estimates of mortal- ity and fertility given there for 1950-55 and 1975-80 are used directly. The esti- mates for 2000 are an average of the values given for 1995-2000 (which of course involve a fair degree of extrapolation based on recent trends) and those projected (using the "medium-variant" assumption) for 2000-05. By this means it is hoped to arrive at estimates of life expectancy and total fertility that are reasonably close to the current situation. In order to weight each country by its population, I use the estimates made by the United Nations for 1950, 1975, and 2000.

China and India are handled differently. As mentioned in the text, I use data for the provinces of China and the states of India. The process by which the na- tional data for these two countries are disaggregated into these subnational com- ponents involves drawing on a variety of sources and making a number of as- sumptions. It is hoped that these somewhat arbitrary assumptions do not introduce major distortions into the overall results. The disaggregation of both India and China uses the UN's national estimates for each country, as used for all other coun- tries, as the targets for the summation of the regional figures. Thus, for example,

CHRIS WILSON 169

the UN estimates imply that total fertility in China in 2000 is 1.82. When the pro- vincial estimates were made, I ensured that the population-weighted average of the provinces matched this target, in order to ensure comparability with the UN estimates.

The population of each of China's provinces was taken from Yao and Yin (1994), and fertility estimates were taken from Coale and Chen (1987), Peng (1991), and Yao (1995). To estimate TFR for 2000, the most recently available provincial data in Yao (1995), for 1990, were reduced pro rata by the ratio of the national TFR in 1990 (2.31) to the UN estimate for 2000 (1.82). This assumption of uniform change over the 1990s is unlikely to be valid, but at the time of writing no information was available upon which to base a more judicious adjustment. Life expectancy estimates for 1975-80 and 2000 were taken from Huang and Liu (1995). When no estimate was available for a province, I assigned to it the life expectancy of the province whose estimate was closest to it at the next available date. The most re- cent estimates of life expectancy provided by Huang and Liu, for 1989-90, when aggregated, gave a national figure very close to the UN estimate for 2000 (70.0) and only a minor pro rata adjustment was required to match that figure. The most conjectural data for China refer to life expectancy in the early 1950s. I was unable to locate any province-level estimates for this index, or indeed for any refined measure of mortality. The only data available were crude death rates and popula- tion age structures from the 1953 census (Fan 1995). With this information I cal- culated a standardized index of mortality and used this to estimate life expectancy for each province. This is unsatisfactory, but appears to be the only option in the absence of more precise data.

The regional estimates for India were based on several sources. The population of each state was taken from census results, with an interpolation between 1971 and 1981 made to provide a 1975 estimate. Estimates of life expectancy for the 1950s are drawn from Sinha and Lahiri (1976). No estimates for total fertility for the same period were available; however, the crude birth rate (CBR) is available for each of the larger states (India 1973). Because the correlation between total fertility and the crude birth rate is usually high, these CBR estimates were used to estimate fertility in each state, relative to the all-India figure of 5.97 given in the UN estimates. Total fertility estimates for the 1970s, again for the larger states, were taken directly from Bhat, Preston, and Dyson (1984). Information for later dates is readily available from the Sample Registration System and the National Family Health Surveys (Gandotra 1998; India 1999).

The largest deficiency in the Indian data used here is the lack of information, until relatively recently, on fertility and mortality for many of the smaller states and territories. For example, of the seven states of northeast India, I was able to find official estimates of total fertility and life expectancy for the 1950s and 1970s only for Assam. Similarly, estimates were available only for the recent period for most of the Union Territories, Himachal Pradesh, and Goa. Information on the state of Jammu and Kashmir was also limited, presumably because of the political and military situation that has prevailed there for much of the last half-century. The total population within these areas of limited data availability is, however, small compared with all-India. Thus the states for which estimates are readily avail- able constitute between 94 and 96 percent of the total population at the three

170 GLOBAL DEMOGRAPHIC CONVERGENCE

dates used here. In this light, the impact of the assumptions made to estimate fer- tility and mortality for these smaller states is limited. The procedure chosen was to assign to each of the missing cells an estimate based on the crude rates, where available. When even crude rates were missing, the state was given the same value as the state whose fertility or mortality most closely matched the missing popula- tion at the next date. When no suitable comparison state was available, the all- India value at the date in question was used.

GNP per head

To calculate the global median GNP per head referred to in the conclusion to the assessment, I took national purchasing-power-parity estimates from the World Bank's World Development Report 2000/2001. Estimates for Chinese province-level data come from Liu et al. (1996), and for the states of India from the Government of India's Economic Survey 1997-98. As with the demographic series, the intra-country GNP estimates were scaled pro rata by the size of each region's population, to ensure that the national total equalled the values given in the World Development Report. Strictly speaking the Chinese and Indian data are not fully adjusted for purchasing power differences, as they do not reflect within-country price differ- entials. However, no internationally comparable regional data were available. More- over, it is unlikely that the biases thus introduced are significant compared with international differences in purchasing power.

Note Preparation of this assessment was aided by ad- vice, assistance, and encouragement from Jalal Abbasi-Shavazi, Judith Banister, Heather Booth, Jean-Claude Chesnais, Tim Dyson, John Haaga, Patrick Heuveline, Donald

Kennedy, Stephen Kunitz, Ronald Lee, Geof- frey McNicoll, Jim Oeppen, Saseendran Pallikadavath, Xizhe Peng, E. A. Wrigley, and Zhongwei Zhao.

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