In this Feb. 1, 2012 file photo, people line up to cross into the United States from Mexicali, Mexico, before dawn in Calexico, California.

In this Feb. 1, 2012 file photo, people line up to cross into the United States from Mexicali, Mexico, before dawn in Calexico, California. (AP Photo)

More Mexicans are leaving the United States than are arriving, according to an analysis from the Pew Research Center.

Government data from both countries also shows that the flow of Mexican immigrants between the United States and Mexico is at its lowest since the 1990s. Survey data from the Mexican government finds that most of the 1 million Mexicans who left the U.S. to return home, between 2009 and 2015, left because they wanted to.

PH_2015-11-19_mexican-immigration-02The number of Mexican immigrants living in the United States peaked at 12.8 million in 2007. That population has declined since then, dropping to 11.7 million in 2014.

Six in 10 (61 percent) of the returned migrants said the desire to reunite with family was the main reason for going back to Mexico. Only 14 percent said they had no choice in the matter because they were deported.

Pew attributes the recent decline to a variety of factors.

“The slow recovery of the U.S. economy after the Great Recession may have made the U.S. less attractive to potential Mexican migrants and may have pushed out some Mexican immigrants as the U.S. job market deteriorated,” according to the analysis.

Stricter enforcement of U.S. immigration laws along the U.S.-Mexico border could also play a part.

In 2013, 28 percent of the 41.3 million immigrants in the United States were from Mexico. Here, Mexican immigrant Martina Juárez, 40, right, poses with her daughter and grandsons in New York, Aug. 26, 2015. (AP Photo)

In 2013, 28 percent of the 41.3 million U.S. immigrants were from Mexico. Here, Mexican immigrant Martina Juárez, 40, right, with her family in New York, Aug. 26, 2015. (AP Photo)

Apprehensions of Mexicans there have fallen to their lowest level since 1971. This increased enforcement means more Mexican immigrants have been deported since 2005.

Mexicans are the largest foreign-born group in the United States. In 2013, 28 percent of the 41.3 million U.S. immigrants were Mexican.

Mexico is also the largest source of America’s illegal immigrants. More than 16 million Mexicans migrated to the United States between 1965 and 2015.

These latest changes could have historic implications, signaling the end of America’s largest wave of immigration from any one country.