The Population Reference Bureau released its 2010 World Population Data Sheet today, focusing on the theme of divergent demographics in developed and developing nations. Population is barely growing in developed nations, where birth rates tend to be low and the number of elderly is increasing rapidly. Developing nations, where birth rates are higher, are projected to account for virtually all world population growth in coming decades.

The data sheet includes a chart showing nations with the world’s oldest populations, all of which are developed countries. At the top is Japan, where 22.6% of the population is 65 and older (in the U.S., the equivalent share is 13%). Another chart shows nations with the youngest populations, all of which are developing countries. At the top is Niger, where 50.1% of the population is under 15 (in the U.S., 20% of the population is under 15).

The data sheet includes 19 population, health and environment measures for more than 200 countries.