Our study indicates that if there is a long-term floor, it is in the neighborhood of 1.7. The United Nations low projection also assumes that the fertility rates can fall as low as 1.7. Thus, the United Nations low projection of population growth should be considered as the most likely scenario for population growth in the first half of the 21st century. Of course, this general world view obscures the important country and regional differences in population growth. Family planning interventions are extremely important, and the rapidly decreasing fertility rates in most of the countries of the world show that there are high rates of return to investments in family planning programs.
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