President Obama announced new action to delay the deportation of about 4 million undocumented immigrants living in the U.S. Here are some numbers to know about immigration. (Julie Percha/The Washington Post)

President Obama announced a big executive action on immigration Thursday night. But while it allows nearly half of illegal immigrants in the United States to avoid deportation, the impact varies significantly by state.

According to data from the Migration Policy Institute, 51 percent of illegal immigrants in Texas and 50 percent in California -- the two states with the largest illegal immigrant populations -- will be temporarily exempted from deportation. But in Maryland and Massachusetts, it's just 35 percent, and in Virginia it's 37 percent.

Aside from California and Texas, at least half of illegal immigrants in Arizona, Colorado, Illinois, Oregon and Utah will be exempted.

Here's how that looks, focusing on states with large illegal immigrant populations (states in gray have very small illegal immigrant populations and are not included):

One thing that stood out to us: Republicans will accuse Democrats of doing this to shore up the Latino vote going forward. But swing states aren't really the biggest beneficiaries, with Virginia mentioned above at 37 percent, Florida at 40 percent, North Carolina at 44 percent and Nevada at 46 percent.

Obama's executive action varies by state because it is focused on illegal immigrants who are parents of children who are citizens or legal permanent residents and have been here for at least five years, which is about 3.7 million of the estimated 11.4 million illegal immigrants in the United States. Another 1.5 million will benefit from the program called Deferred Action for Childhood Arrivals (DACA), which Obama first announced in 2012 and allows young illegal immigrants who came to the United States as children to stay. That program was expanded by about 300,000 after Thursday's announcement

The other 6.2 million illegal immigrants are not covered by Obama's executive action.