the year 1800, total fertility rates of 4.5 to 7.5 were common around the world. After this TFR declined only slightly and up until the 1960s the global average TFR was still 5. Since then, global average TFR has dropped steadily to less than half that number, 2.3 births per woman in 2023.

The United Nations predicts that global fertility will continue to decline for the remainder of this century and reach a below-replacement level of 1.8 by 2100, and that world population