TFR

 Total fertility rate TFR that if sustained leads to each new generation being less populous than the older, previous one in a given area. In developed countries sub-replacement fertility is any rate below approximately 2.1 children born per woman, but the threshold can be as high as 3.4 in some developing countries because of higher mortality rates. Taken globally, the total fertility rate at replacement was 2.33 children per woman in 2003. This can be translated as 2 children per woman to replace the parents, plus a third of a child to make up for the higher probability of boys born and mortality prior to the end of their fertile life. Developing countries have a higher TFR because they have more kids because they don't have birth control. Countries that are poor can't afford to have protection therefore they keep producing kids. The countries or areas that have the lowest fertility are in developed parts of East and Southeast Asia: Singapore, Macau, Taiwan, Hong Kong and South Korea.