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.
Demographics of Singapore
After World War II, in the period from 1947 to 1957, Singapore saw a massive population increase mostly due to increased number of native births. The birth rate rose and the death rate fell; the average annual growth rate was 4.4%, of which 1% was due to immigration; Singapore experienced its highest birth rate in 1957 at 42.7 per thousand individuals. (This was also the same year the United States saw its peak birth rate.)