President Donald Trump appears to think building a wall on the U.S.-Mexico border will solve unauthorized immigration and other issues at the border. Stats from the last few years tell a completely different story.

Trump signed two executive orders Wednesday that call for the immediate construction of a wall and issue directives to crack down on unauthorized immigration, increase security at the southern border and expand agencies deportation powers.

The order describes building the wall as a measure to prevent illegal immigration, drug and human trafficking, and acts of terrorism. Prioritizing a wall with an estimated cost in the billions has been widely condemned by Latino groups and lawmakers as a discriminatory attack on immigrants.

Building a wall to keep Mexicans out is also out of touch with the current realities of unauthorized immigration. Since the recession, more undocumented Mexican immigrants are actually leaving the country than entering it, according to the Pew Research Center.

And as the Mexican economy has improved, the number of people attempting to illegally cross into the U.S. from Mexico has dropped dramatically over the last 15 years, according to Quartz:

As of 2014, the majority of the 11 million undocumented immigrants living in the U.S. are from Mexico, according to Pews population estimates, but their numbers have been declining .

At the same time, unauthorized immigration from other countries has risen, driven by people coming from Central America, Asia and sub-Saharan Africa. Pew notes that many of the people from those regions are entering the country legally and overstaying their visas something a wall wont prevent.