The findings are “a reflection of changes in the overall economy” since the recession, according to demographics experts Jeffrey S. Passel and D’Vera Cohn, essentially mirroring rises and declines in the overall U.S. economy.

The share of all unauthorized immigrant workers with management and professional jobs grew to 13 percent in 2012 from 10 percent in 2007, according to the study, while the share with construction or production jobs declined to 29 percent from 34 percent.

“Certainly the economy has moved more in that direction. Overall the white collar workforce has grown and the blue-collar work force has declined in the last few years, so in that sense the unauthorized immigrant workforce is just reflecting the larger economic trend,” Cohn said in an interview today. “What we don’t know is whether the people who” previously were in blue collar jobs are the ones holding those jobs now.

“It seems implausible that people who were construction laborers five years ago are now software developers,” she added. “In many cases these are different people, although some people may have moved up the ladder.”

Passel noted that many illegal immigrants have now lived and worked in the U.S for ten years or more and have been able to land better jobs in their occupational  fields, such as managers, while others have obtained work permits under the president’s executive action or decided to overstay their visas. “Remember, now there are about 600,000 people who have gotten work permits under the Dream Act, and those are all people who went to college pretty much,” he said.

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