Republican presidential candidate Marco Rubio recently claimed that there are "more illegal immigrants" in the U.S. than five years ago, research studies show that the population of undocumented immigrants has actually been on the decline in recent years.

While speaking on NBC's "Meet the Press" Sunday, the Republican presidential hopeful asserted that there are more undocumented residents living in the counrty than there were in 2011.

"We are worse off today than we were five years ago. We have more illegal immigrants here," said the Florida senator, reports PolitiFact. "We have two unconstitutional executive orders on amnesty. I went to Washington to fix a problem."

However, in contrast, several studies show that illegal immigration in the U.S. has either stabilized or decreased since its peak in 2007 throughout 2014 (the year with the latest available data).

According to a Pew Research Center report released last July, the unauthorized immigrant population peaked at 12.2 million in 2007. However, by 2010, the number had dropped down to 11.4 million. Meanwhile, four years later, the number of undocumented immigrants has dipped even further to 11.3 million.

Research from Pew found that the population of unauthorized immigrants stabilized due to the millions of immigrants who were either deported under the Obama administration, left on their own or died off.

Another Pew report issued last November found that the number of Mexican immigrants has been on the decline, dropping from 6.9 million in 2007 to 5.6 million in 2014. As a result, the decline in Mexican immigrants is the main reason why illegal immigration stopped growing, said Robert Warren, a demographer and senior visiting fellow at the Center for Migration Studies.

Likewise, a report from the Center for Migration Studies finds that the belief that illegal immigration is growing is a misconception.

''One reason for the high and sustained level of interest in undocumented immigration is the widespread belief that the trend in the undocumented population is ever upward,'' the 15-page report says, according to The Boston Globe. ''This paper shows that this belief is mistaken and that, in fact, the undocumented population has been decreasing for more than a half a decade.''