As a border state, we hear a lot about immigrants who illegally cross the U.S.-Mexico border. But, this year, it was Central Americans who officials say helped drive an increase in immigration arrests.

Border Patrol apprehensions surged 23 percent to nearly 416,000 in the year that ended on Sept. 30, 2016, according to recently released statistics from the Department of Homeland Security.

But, they’re still not as high as they have been in recent years, according to Jens Manuel Krogstad with the Pew Research Center in Washington, D.C.

“We reached a peak in apprehensions a few years ago in 2011 and 2012, a recent peak,” he said. “But, still the overall numbers are still quite a bit lower than we saw 10 or 15 years ago.”

So, what drives this? According to Krogstad, it has to do with border enforcement, “but it also has to do with how many people are trying to cross in the first place.”

Ten or 15 years ago, we were seeing a lot more people trying to cross. “We were seeing a million — more than 1 million apprehensions at the U.S.-Mexico border,” Krogstad said.

And, at that time, the immigrants coming here were mostly adult men from Mexico, according to Krogstad.

But, in 2014, we saw a huge number of unaccompanied minors mostly from Central America crossing the border. Those numbers dropped off in 2015 and then went back up last year.

The Department of Homeland Security reports that they apprehended almost 60,000 unaccompanied children in 2016 and even more families, more than 77,000 of them last year.

“A lot of the factors that were driving people to come the United States are still in place,” Krogstad said. “There’s (an) unstable political climate, there’s violence, especially by gangs that is plaguing metro areas.”

And, as long as those things are still in place, there’s still an incentive for Central Americans to try to make the journey to the United States, he said.

Economics and the job market are not as much of an incentive for immigration from Mexico, anymore, Krogstad said.

We saw that drop off when the U.S. economy tanked during the Great Recession, he said. And Pew has done some research on what Mexicans think about the U.S. and he said, that has been shifting, too.

“A growing number of Mexicans who are living in Mexico tell us they don’t see that much of a difference between the two countries when it comes to standard of living,” he said. “So, those economic drivers aren’t what they once were.”

He also said the reasons people give Pew for immigrating aren’t just economic.

“Just about as high are family reasons, people leaving to join family or friends in the United States,” he said. “So, as you see those ties loosen a little bit over time, you maybe lose that other motivation, the motivation to join family.”