U.S. Border Patrol
People are taken into custody by the U.S. Border Patrol near Falfurrias, Texas. Reuters / Eric Thayer

A new study finds that the number of Mexican unauthorized immigrants apprehended at U.S. borders has dropped to historic lows. More non-Mexicans than Mexicans were detained by the Border Patrol in 2014 for the first time on record, according to the Pew Research Center analysis of more than 60 years of Border Patrol data.

Mexicans detained at the border totaled 229,178 in 2014, compared to 257,473 non-Mexicans apprehended during the same period last year. By contrast, about 809,000 Mexicans were apprehended by the Border Patrol in 2007, compared to just 68,000 non-Mexican apprehensions. The number of Mexican apprehensions has not been this low since 1970, when 219,254 Mexican unauthorized immigrants were detained and non-Mexican apprehensions totaled just 11,862, according to the study.

This demographic shift in migration patterns is in part due to a recent surge in unaccompanied Central American child migrants crossing the border, according to the study. Nearly 52,000 unaccompanied minors from El Salvador, Guatemala and Honduras were detained at the U.S.-Mexico border, compared to just 16,000 unaccompanied Mexican children, according to U.S. Customs and Border Protection data.

While the number of Mexican apprehensions has dramatically fallen, Mexicans still account for 52 percent of the nation’s illegal immigrant population. The research indicates that fewer illegal immigrants are migrating to the United States from Mexico; however, those who are already in the country are staying and many will receive deportation relief from President Barack Obama’s extended deferred action program.

Obama used his executive authority on Nov. 20 to defer deportation for millions of immigrants – a move that many Republicans in Congress consider unconstitutional. Nearly half the nation has signed a legal coalition to bring a lawsuit against the president for his executive action on immigration.