A new study shows that more Mexican immigrants are leaving than entering the U.S.

{mosads}The report, published Thursday by the Pew Research Center, said a sluggish economy and a desire to be reunited with family are causing Mexican immigrants, both legal and illegal, to go back to their native country.

Pew found that more than 1 million Mexican immigrants and their families, including American-born children, left the U.S. for Mexico from 2009 to 2014. Over that same span, 870,000 Mexicans entered the U.S.

The study, which relies on government census data from both countries, acknowledges that it is difficult to measure the inflow of immigration into the U.S. from Mexico.

But Mark Hugo Lopez, Pew’s director of Hispanic research, told The Associated Press that the findings demonstrate the period of mass migration from Mexico to the U.S. is “at an end.”

“This is something that we’ve seen coming,” Lopez said. “It’s been almost 10 years that migration from Mexico has really slowed down.”

The Pew study estimates that there are 5.6 million illegal immigrants currently residing in the U.S., down from 6.9 million in 2007.

The study notes that enhanced border security m

01ay be playing a role in deterring illegal immigration, but emphasizes that a struggling U.S. economy is the primary factor driving the exodus.

Immigration has become one of the primary issues in the current political climate, particularly among Republicans.

GOP primary front-runner Donald Trump has campaigned on curbing illegal immigration, winning supporters by promising to force Mexico to pay for a wall on the U.S.-Mexico border.