The number of undocumented immigrants living in the U.S. has been stagnant since the recession, and estimates indicate "no sign" of a migration increase.

Preliminary Pew Research Center estimates, based on U.S. Census Bureau's American Community Survey and Current Population Survey, found 11.3 million "unauthorized" immigrants lived in the U.S. as of March 2013. In 2012, 11.2 million unauthorized immigrants lived in the U.S.

"The population had risen briskly for decades before plunging during the Great Recession of 2007 to 2009," noted Pew Research Center's report by Jeffrey Passel, D'vera Cohn, Jens Manuel Krogstad and Ana Gonzalez-Barrera. "As growth of this group has stalled, there has been a recent sharp rise in the median length of time that unauthorized immigrants have lived in the U.S."

The preliminary estimates indicated the average time an unauthorized immigrant adult lived in the U.S. was 13 years. Ten years earlier, the median time for adults was less than eight years.

President Barack Obama is projected to announce an executive action addressing the immigration system due to inaction from Congress.

"More and more, America is home to immigrants who have put down roots and want to contribute as fully as they can. Right now our broken immigration system is holding them back," said National Immigration Forum Executive Director Ali Noorani in a statement.

According to Noorani, the Pew Research Center's report shows America's "potential," adding, "America will succeed if new Americans have the opportunities, skills and status to reach their fullest potential. All of us will benefit when we have an immigration process that welcomes and integrates new Americans."

"Furthermore, the decrease in the undocumented population is further evidence that our border is as secure as it has ever been. To keep this trend going in a way that benefits our families and our economy, Congress and the administration need to work together on immigration reform," said Noorani.

In comparison to 1990, the number of unauthorized immigrants living in the U.S. was 3.5 million, but the figure tripled to 12.2 million by 2007.

The Pew Research Center data disclosed that 4 million authorized immigrant adults are living in the country with U.S.-born children. Of the 4 million immigrants, 3.7 million are not protected from deportation under Obama's Deferred Action for Childhood Arrivals (DACA) program, which has granted temporary stay for over 570,000 undocumented immigrant youths, or the Temporary Protected Status (TPS) program.

The report comes as the United Nations Population Division said approximately 45.8 million people living in the U.S. were born in another country. Nearly 13 million of them are originally from Mexico.