Marchers carry signs in support of immigrant rights as thousands of protesters march up Broadway during a May Day immigration rally in Los Angeles. (Reuters)

Even as President Obama prepares to announce his immigration executive action, the percentage of illegal immigrants in the United States has dropped. While the undocumented comprised an estimated 4 percent of the population in 2009, that number was down to 3.5 percent in 2012, according to data from Pew. The raw number was down from an estimated 12.2 million in 2009 to 11.2 million in 2012.

The reasons are mostly twofold: (1) the economic depression, which made immigrating illegally less attractive, and (2) the unprecedented deportations that have taken place during the Obama Administration -- more than 2 million, as of earlier this year.

But lest anyone think Obama's executive action won't potentially affect lots and lots of people, I bring you this:

The below map, from Pew, shows the percentage of K-12 students in each state who have at least one undocumented parent.

Courtesy: Pew Hispanic Center

At the high end is Nevada. While 7.6 percent of Nevada residents are illegal immigrants, more than one in six K-12 students (17.7 percent) has at least one undocumented immigrant for a parent.

That number is 13.2 percent in California, 13.1 percent in Texas and 11 percent in Arizona. In each case, the number of children with undocumented parents is more than twice the overall undocumented population.

Another 20 states have more than 5 percent of students with an undocumented parent. Overall, 6.9 percent of American students -- about one in 14 -- have at least one illegal immigrant for a parent. That's compared to the 3.5 percent of Americans who are illegal immigrants.

It's a reminder that illegal immigrants are not the only ones who have a significant stake in what happens with Obama's executive order; so do the many more millions of people in their families.