INThOCUCTiON XV developed ceoy populaton in 2025 is only 0.3 percent higher than Ist year's projection and 1 pI omd lower ta d U.N. projection. **As** shown in Figure 2, the differncs are wider for more doveoped coutoe. The current projection for 2025 is 3 percent higher than lst year's projection **and** 1.2 _percePt_ higor than the U.N. projetion. Thee differences are due not only to differences in procedur for projecting vital rtes but also to slightly different estimates of current population **and** vital rae.

Since 1975, major world regions have been growing at quite different rates, which are changing in differt directions. In Sub-Sahan Africa, the population growth rate has been iwtOinc stdily from anD ady high 2.8 percent in the 197o to 3.1 perent in the most reent five-year perio (1985-90). In the Asia reion (excluding developed countries), growth rates declined betwoe 1975 and 1985 from 1.9 to 1.8 percent, but have inched up recently a China's fertility tition stopped short of replacement. In North Africa and the Middle East, population growth rates show a slight inrease, from 2.8 peret in 1975-80 to 3.0 percent annually in 1985-90. Slowing population growth rate are observed in the les developed counts of Latin America and the Caribbea (down from 2.3 to 2.0 percent annually) **and** for the more developed countries (from 0.7 to 0.5 percnt annually). Growth is spread unevenly, with urban areas generaly growing faster than rural areas, as Box 3 decribes.

hes differential growth rats will continue for the next decade (as Figure 3 illustrates) **an** for some time into the future. Current and projected population and growth rates for five major rgions are shown in Tabls 1 and 2. (All tables appear at the end of this section, beginning on page xxxviii.) The prcentage distribution of world population by these regions is represented for 1985, 2000, **and** 2025 in Figure 4.

Asia, with the two most populous countries in the world, accounts for 59 percent of the world population, and currently contributes 61 percent of the annual increse, or about 56 million people. By 2025, Asia will still be adding some 48 million people annually to the world population. Averge annual contributions of other major regions between 1990 and 2025 will be much less: 27.3 million for Africa, 9.6 million for America, 2.6 million for Europe, and 0.3 million for Oceania. Asia's annual contribution to world population growth will undergo the most rapid decline (14 percent between 1990 and 2025). However, even with a reduced rate of growth and a decline in its averge contribution to world population increase, Asia's population by 2025 will be just about 5 billion-approximately the size of the entire world population in 1987. The rising population densities reulting from this growth are shown in Figure _5._ Two major Asian subregions have opposite prospects. East and Southeast Asia (which includes China) now contains one-third of the world population. Its share will fail to 30 percent in 2025 **nd** to 25 percent by 2100. South Asia (which include India) ranks second in population and contains 22 percent of the world population. Its share will increase to 25 percent by 2100.

Africa currently is the fourth largest among the five major regions, with about 12 percent of the world population. With an annual growth rate of 2.9 percent in 1990, Africa by the year 2000 will be the second lgest region, with 14 percent of the world population. The growth rate will fall slowly to 2.1 percent by 2020-25, and the region will have 19 percent of world population by 2025. Afiica's contribution to world population growth will increae by 58 percent between 1990 and 2025. By that time, its population will be two and a half times its current size. Africa's population is now 20 parcent the size of Asia's, and will be 32 percent by 2025. As Figure 6 shows, Africa is considebly le dense than Asia, but densities will rise rapidly.

Among African subregions, East, West, and North Africa have 42, 37, and 22 percent