(CNN) - Since the start of the recession, the birth rate in America has been declining.
Last year it plunged to its lowest level since at least 1920, according to a study released by the Pew Research Center.
The overall birth rate in 2011 was 63.2 per 1,000 women of childbearing age.
The biggest dip in recent years is among immigrant women.
The number of foreign-born women having babies dropped 14 percent between 2007 and 2010.
Among women from Mexico, the birth rate fell by 23 percent.
The birth rate for U.S. born women declined 6 percent in that same period.