On Tuesday, a Pew Research Center white paper found that while the number of illegal Mexican immigrants has decreased compared with other countries, the number of illegal immigrants as a whole who stay long-term has risen considerably.

Based off of government data, Pew found that while there were 6.4 million illegal Mexican immigrants in 2009, there were only 5.8 million in 2014—a decrease of more than half a million. But the number of illegal immigrants from other countries increased and stabilized during that same period, from 5 million to 5.3 million.