Key Takeaways:

* The total fertility rate (TFR), or the average number of births per woman over her entire reproductive life, is one factor affecting population growth. Trends in the TFR have implications for the world’s demography.

* Although poor countries have a higher TFR than rich countries, the rate has been declining in both for 60 years. This has narrowed the TFR gap between the poorest and richest countries from three children per woman to less than one child per woman.

* In rich countries, the TFR has been lower than the rate needed to maintain population levels for a few decades. But the TFR in low-income countries remains higher than the replacement rate.