First time since the 1930s that flow of illegal Mexicans into US might have been reversed?

Personally, I can't see how this small change is statistically significant, but nonetheless here is what Pew finds:

The largest wave of immigration in history from a single country to the United States has come to a standstill. After four decades that brought 12 million current immigrants—more than half of whom came illegally—the net migration flow from Mexico to the U.S. has stopped and may have reversed. . . .