# INTRODUCTION

**his ppe** provides populatior projections for each country, economy, or territory in one World **Dak** region, as well as for notuorrower countries in the same geographic<sup>area. Three</sup> companion papers provide similar projections for the other Bank regions. Each paper also contains projections for groups of countries in the same geographic region, or at the same income<sup>level.</sup>

These projections are updated annually. In this 1990-91 edition, projections are provided in a pew formal to permit the inclusion of data on recent demographic trends.<sup>lhis introducti--</sup> (similar across the four regional papers) explains the format of the data tables<sup>and summarizes</sup> main demographic trends and projection results.

Projection methods have changed only marginally since the previous edition. Essentially, recent country-specific data about levels and trends in fertility, mortaliiy, and international migration are appliod to available age-sex distributions in order to obtain short-run orojections.<sup>Long-run</sup> projections, up to 2150, are also made under the assumptions that fertility<sup>and mortality eventually</sup> become stable and net international migration declines to zero. One change in procedures<sup>from last</sup> year involves allowing a slightly higher long-run level of life expectancy. This and<sup>other details of</sup> the methodology amre described in an appendix, which also provides an cxplanation o; C.ta sources.

Caution is appropriate with all projections like these. They essentially involve working out the implications of assumptions about demographic trends. None<sup>of the results should be</sup> interpreted as indicating certitude about the future. Instead, they should be red4 with the universal qualifier that population will follow the indicated path if the assumptions prove to be<sup>cor.ict.</sup>

## FORMAT OF TABLES

Each country, economy, or territory is covered in two pages: the first to provide recent demographic trends and the second to provide population projections.

The first page (illustrated and explained in Box 1) provides estimates of total population and population composition for 1980, 1985, and 1990, as well as estimates of vital rates for the fiveyear pericds preceding each of these dates (1975-80, 1980-85, and 1985-90).

The second page (illustrated and explained in Box 2) provides projections for every five years from 1990 to 2025, and for every 25 years from 2025 to 2150. Various indicators<sup>of vital rates</sup> are given for the intervening five-year or 25-year periods. The second page<sup>also includes population</sup> pyramids and graphical comparisons between the country and the region and the income group<sup>to</sup> which it belongs.

Unlike previous editions, this edition does not provide detailed age-sex<sup>structures. (Bank</sup> staff can still obtain these from the authors.) Instead, the population pyramids illustrated<sup>in Box 2</sup> show the current and a projected age-sex distribution.

The countries covered are 181 in all, tol'ther with six groups of "other" countries too small to allow independent treatment. Two changes in international boundaries--the unification<sup>of the</sup> Yemens and the Germanys--are too recent to be reflected in these tables, which still treat<sup>them as four</sup> separate entities.

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