But only 12 percent of undocumented immigrants say they came to the country specifically to reunite with a spouse or other family member. Nearly four in 10 say they came for better jobs and better opportunity, while 38 percent say they believed the United States would offer a better life for their children. Some four percent said they were seeking to escape political repression.

More than two-thirds (68 percent) have been in the country for over a decade, and another 22 percent have been in the country at least five years. Nearly a quarter of undocumented immigrants arrived in the United States below the age of 18, and more than eight in 10 of all persons who entered or remained in the country illegally did so when they were under 30.

"They have deep roots in America, with strong family and social connections to U.S. citizens, painting a portrait of a community that is very integrated into the American fabric, and hopeful of a chance to gain legal status and ultimately citizenship," Latino Decisions' Matt Barreto and Gary Segura say in a statement.

The survey also found that 71 percent of undocumented immigrants own their own cars, while 15 percent say they own their own homes.