A new study from the Pew Research Center crunched six decades worth of US Border Patrol data and found that 2014 was the first time in history the agency apprehended more non-Mexicans than Mexicans crossing illegally into the US.

According to recently published Border Patrol data, the agency caught more than 229,000 Mexicans in the 2014 fiscal year, compared to more than 257,000 non-Mexicans. Those figures are a seismic shift from 2007, when Border Patrol agents captured 809,000 Mexicans and just 68,000 non-Mexicans.

"It is a pretty striking milestone," Jens Manuel Krogstad, co-author of the Pew report, told VICE News. "It's the first time on record this has happened."

For 1st time on record, more non-Mexicans than Mexicans apprehended at U.S. borders — Pew Research Center (@pewresearch)December 30, 2014

Krogstad said the findings reaffirm previous evidence that Mexican migration to the US is on the decline. A 2012 Pew report that analyzed data from both the Mexican and US governments found migration had "come to a standstill," and may have actually rolled back.

The recent Pew study found that the number of Mexican immigrants caught trying to cross the border peaked at 1.6 million in 2000. To find a year when Mexican immigration was roughly equivalent to 2014 statistics, the Pew researchers had to go all the way back to 1970, when 219,000 Mexicans were apprehended. That same year, just 12,000 non-Mexicans were taken into custody.

"We had reports and studied this trend of declining Mexican migration to the US — this was just another sign that this was taking place," Krogstad said. "Migration started to dry up since the great recession in 2008. That's been for a variety of reasons — some of them are economic, there are fewer jobs in the US, and economic conditions in Mexico also contributed. Also, there's increased border enforcement."

Overall, more than 486,000 immigrants were stopped from entering the US in 2014 — a 16 percent increase from 2013.

One of the driving factors was the steep rise in Central Americans coming to the US, particularly unaccompanied children. According to US Border Patrol, 68,631 children tried to cross the border in the 2014 fiscal year, mostly from Honduras, El Salvador, and Guatemala. The wave of vulnerable migrants triggered a crisis over the summer that forced authorities to open emergency shelters and launch advertising campaigns in Central American countries that urged families not to make the dangerous journey north.

"It's no surprise given how violent it's gotten in Central America that those numbers are up," Wendy Feliz, a spokeswoman for the American Immigration Council, told VICE News. "That doesn't surprise anyone. It used to be all economic reasons, now it's gotten to the point where people are actually seeking safety."

Despite the recent dip, Mexicans still account for the majority of undocumented immigrants in the US — but barely. According to a previous Pew Research Center study, there are an estimated 5.9 million Mexicans living in the US without the proper authorization, comprising roughly 52 percent of America's undocumented population.

The Pew border apprehensions report noted that the number of Americans who say increased border security should be a priority rose from 25 percent in February 2013 to 33 percent in August 2014. The number of Border Patrol agents has more than doubled since 2004, rising from 10,000 agents then to more than 21,000 today.

'Overall, more than 486,000 immigrants were stopped from entering the US in 2014 — a 16 percent increase from 2013.'

On November 20, 2014, President Barack Obama announced an executive action on immigration that provides relief from the threat of deportation to about 4 million of the estimated 11 million undocumented people in the US. Obama's plan offers a reprieve to undocumented parents of US citizens and permanent residents who have been in the US for at least five years, and expands his 2012 Deferred Action for Childhood Arrivals (DACA) program.

Feliz noted that the president's immigration action will be accompanied by yet-to-be specified steps to increase border security.

"A lot of it is still vague and being developed," Feliz said. "Certainly, in exchange for the affirmative relief program there will be more buildup at the border."

Going forward, Feliz said she hopes the US will treat more of the Central American migrants coming to the US as refugees and asylum seekers, rather than lawbreakers. She pointed to a program launched earlier this month by the US State Department that allows for in-country refugee processing in El Salvador, Guatemala, and Honduras.

The State Department said the program will "provide a safe, legal, and orderly alternative to the dangerous journey that some children are currently undertaking to the United States."

Follow Keegan Hamilton on Twitter: @keegan_hamilton