Total fertility rate (TFR) refers to the actual average number of children born to a woman over her lifetime.
An encouraging piece of news is that ~70 of the world's 192 nations had TFR equal to or lower than replacement level fertility (RLF) by the early 2000's. In fact, the combined population of nations with such low TFR's was, by mid-2003, equal to ~ 40% of the total global population. (Note -- these nations aren't all stable or declining in population yet -- largely because of momentum introduced by age structures -- but they will become so if current trends continue.)
TFR for the U.S. in mid-2012 was 1.9 children per woman.
This is about the same as RLF , and TFR in the US has been at RLF since 1972.
Notice any contradiction here? The US population is growing at 0.5% per year (ignoring immigration) yet the average woman in this country has been reproducing only at replacement levels for over 30 years. How can this be?? If our TFR is equal to RLF, why aren't we at ZPG? Read the next section to find out (use ">>," below, to get there).
(To return to the previous section on replacement level fertility, click the box labeled "<<" and to return to the master directory for the BI301 web page, click the box labeled "CONTENTS.")