Birth rate
The region of Sub-Saharan Africa has the highest birth rate in the world. As of 2016, Niger, Mali, Uganda, Zambia, and Burundi have the highest birth rates in the world. This is part of the fertility-income paradox, as these countries are very poor, and it may seem counter-intuitive for families there to have so many children. The inverse relationship between income and fertility has been termed a "demographic-economic "paradox"" by the notion that greater means would enable the production of more offspring as suggested by the influential Thomas Malthus.
Birth rate
The United States population growth is at an historical low level as the United States current birth rates are the lowest ever recorded. The low birth rates in the contemporary United States can possibly be ascribed to the recession, which led women to postpone having children and fewer immigrants coming to the US. The current US birth rates are not high enough to maintain the size of the U.S. population, according to The Economist.