By Karen Ridder | Monday, 14 Sep 2015 01:04 PM

California has the largest number of illegal immigrants in the United States, with an estimated 2.4 million unauthorized immigrants making up about 6.3 percent of the state’s total population, according to the Pew Research Center.

While the number of illegal immigrants in California continues to rise, the increase in other areas of the country is happening at a much faster rate. The nationwide average increase in illegal immigrant populations was about 250 percent from 1990 to 2007, the Pew study said. In California, the rise was 88 percent.

In the early 1990s, California had over 40 percent of the total illegal immigrant population in the country. That rate had fallen to just about 23 percent by 2007. California saw a decline in illegal immigration from 2009 to 2012.

The Pew Research Center attributed the fall in the numbers of illegal immigrant populations in California to the fact that more immigrants are simply moving to other states. In 2012, while California had more numbers than any other state, the highest percentage of the overall population went to Nevada, where unauthorized immigrants accounted for 7.6 percent of the state’s population.

The Migration Policy Institute estimated the number of illegal immigrants living in California to be much higher than the Pew Research Center's estimate. The Migration Policy Institute estimated a little more than 3 million undocumented residents living in the state. Of those, 70 percent are from Mexico. About 412,000 come from Asian countries. Another 480,000 come from Central America and China.

Illegal immigration in California brings in high numbers of marginally educated immigrants. About 11 percent of the adults who are undocumented immigrants in California are believed to have a college level education, according to the Migration Policy Institute. About 32 percent have a high school diploma or some college. That leaves 57 percent with education below the level of a high school diploma or GED.