From 2007 to 2009, the United States had seen a sharp decline in the number of immigrants entering the country illegally. According to a new report released by the Pew Research Center on Tuesday, this population appears to be on the rise again.
The number of undocumented immigrants had peaked at 12.2 million in 2007 and dropped to 11.3 million in 2009. As of May 2012, this population had risen to 11.7 million, reports Pew Research's latest data.
"As a whole, with the recession ending, the decrease in illegal immigration has stopped," said Pew Research Senior Demographer Jeffrey Passel.
The report found that six states -- California, Florida, New Jersey, Illinois, New York and Texas -- were home to 60 percent of the unauthorized immigrant population. Texas was the only state with increases but no decrease in its unauthorized immigrant population over the 2007-2011 period.
"The numbers remind us the problem of illegal immigration isn't going away anytime soon, unless we take steps to enforce the laws or have legalization of those here illegally," said Steve A. Camarota, director of research at the Center for Immigration Studies.
Pew Research Center reported that most unauthorized immigrants are from Mexico, making up 52 percent of immigrants in the U.S. illegally, but this number has declined since 2007.