A sharp decline in fertility rates in the United States that started in 2008 is closely linked to the souring of the economy that began about the same time, according to a new analysis of multiple economic and demographic data sources by the Pew Research Center.

The year 2007 marked a record high number of births in the U.S.—4,316,233. Since then, births have been declining even as the U.S. population continues to grow. Preliminary data for 2009 indicate that the number of births dropped to 4,131,018, the lowest number since 2004. Provisional data shows that in 2010 births numbered just over 4 million (4,007,000).

A state-level look at fertility rates illustrates the strength of the correlation between lower birth rates and economic distress. States experiencing the largest economic declines in 2007 and 2008 were most likely to experience relatively large fertility declines from 2008 to 2009, according to the analysis. States with relatively minor economic declines were likely to experience relatively small declines.

Between 2007 and 2009, the U.S. fertility rate—which controls for variations in the size of the female population of childbearing age—fell from 69.6 births per thousand women ages 15-44 to 66.7 births per 2009. Provisional data for 2010 indicates a further drop to 64.7 births per thousand women ages 15-44. Read More

Russell Heimlich  is a former web developer at Pew Research Center.