Washington, D.C. - More Mexican immigrants have returned to Mexico from the U.S. than have migrated here since the end of the Great Recession, according to a new Pew Research Center analysis of newly available government data from both countries.

The same data sources also show the overall flow of Mexican immigrants between the two countries is at its smallest since the 1990s, mostly due to a drop in the number of Mexican immigrants coming to the U.S.

From 2009 to 2014, 1 million Mexicans and their families (including U.S.-born children) left the U.S. for Mexico, according to data from the 2014 Mexican National Survey of Demographic Dynamics (ENADID). U.S. census data for the same period show an estimated 870,000 Mexican nationals left Mexico to come to the Unites States, a smaller number than the flow of families from the U.S. to Mexico.

Measuring migration flows between Mexico and the U.S. is challenging because there are no official counts of how many Mexican immigrants enter and leave the U.S. each year. This report uses the best available government data from both countries to estimate the size of these flows. The Mexican data sources - a national household survey, and two national censuses - asked comparable questions about household members' migration to and from Mexico over the five years previous to each survey or census date. In addition, estimates of Mexican migration to the U.S. come from U.S. Census Bureau data, adjusted for undercount, on the number of Mexican immigrants who live in the U.S. (Click HERE for more details.)

A majority of the 1 million who left the U.S. for Mexico between 2009 and 2014 left of their own accord, according to the Mexican government's ENADID survey data. The Mexican survey also showed that six in ten (61%) return migrants – those who reported they had been living in the U.S. five years earlier but as of 2014 were back in Mexico – cited family reunification as the main reason for their return. By comparison, 14% of Mexico's return migrants said the reason for their return was deportation from the U.S.