Births have overtaken immigration as the main driver of population growth among Mexican-Americans, according to a report released today by the Pew Hispanic Center that uses U.S. and Mexican census data. The pattern from 2000-2010 was a change from the previous two decades, when births to Mexican-American mothers in the U.S. were matched or surpassed by the number of new immigrant arrivals.

The birth trend is largely attributable to the surge of immigration from Mexico in recent decades. The report uses data from the Current Population Survey taken by the Census Bureau, as well as Mexican government data on migration of Mexicans in and out of that country. Immigration to the U.S. from Mexico ebbed in the 2000s compared with the 1990s.