One million illegal immigrants have left the U.S. since January, according to a new study.

The study was conducted by the Center for Immigration Studies and released Thursday, based on Census Bureau’s monthly surveys.

The group is a self-described non-partisan group whom critics say is an anti-immigration think tank. 

The report concludes 601,000 illegal immigrants left the workforce from January through May, and the total number of illegal immigrants in the U.S. dropped by 957,000.

“It looks like there’s been a Trump effect on the number of illegal immigrants in the country, based on the best data that we have,” the lead author of the study, Steven A. Camarota, told The Washington Times.

Camarota estimates there are 14.8 million illegal immigrants in the country, which is 1 million less than his estimates when President Trump took office in January.

The report also comes as the Trump administration cracks down on illegal entries at the southern U.S. border and aggressively seeks to find, detain and deport illegal immigrants, in a plan that also accommodates self-deportation.

As the agricultural industry has raised concerns about its migrant workforce disappearing, Camarota the deportations at farms opens up more jobs for Americans.

“I think that this is good news, particularly for less-educated Americans who are likely to see a rise in wages,” Camarota said. “Maybe it will even be helpful in dragging some of these non-college-educated men who are working age back into the labor force.”