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 Hong Kong
At the end of the 20th century, Hong Kong had one of the lowest birth rates in the world. However, the number of births doubled in the decade between 2001 and 2011, largely due to an increase in the number of children born in Hong Kong to women with residence in Mainland China. In 2001 there were 7,810 births to Mainland women (16%) out of a total of 48,219 births. This increased to 37,253 births to Mainland women (45%) out of a total of 82,095 births.