The undocumented immigrant population has been stable since the start of the Great Recession, shifting longstanding trends related to the undocumented population, particularly among undocumented Mexicans, who once represented about half of undocumented immigrants.

Pew Research estimated that 11.3 million undocumented immigrants lived in the U.S. in 2014, basing that approximation on government data. The numbers indicate that the immigrant population has remained stable for five years, after nearly two decades of fluctuation. The newfound stability is contrary to past immigration trends.

The undocumented immigrant population rose rapidly throughout 1990s and the 2000s. An estimated 3.5 million immigrants lived in the U.S. in 1990, and it peaked at 12.2 million in 2007. However, the number declined abruptly during the Great Recession of 2007-09, predominately due to a dip in immigration from Mexico.

Undocumented immigrant influx slowed in recent years due to the fact there are roughly an equal number of U.S.-dwelling foreign born individuals and undocumented individuals who've been deported, converted legal status, left the U.S., or died, according to Pew analysis. The new undocumented immigrant total includes people who've entered the country illegally, as well as individual who've arrived with legal visas and remained after the expiration of their visa. It also includes unauthorized individuals who've been granted temporary relief from deportation thanks to a number of federal programs. Since 2009, there've been approximately 350,000 new arrivals each year, and 100,000 of those new arrivals of undocumented individuals are Mexican, which a much smaller number than in the past.

Since the Great Recession occurred, undocumented immigrants have been less likely to emigrate. The number of long-term undocumented residents doubled over the last decade or more (35 percent in 2000 to 62 percent in 2012). However, in 2012 just 15 percent of undocumented immigrants lived in the U.S. for five years or less. Compare that to 2000, where 38 percent of undocumented immigrants lived in the U.S. for five years or less.

Additionally, Pew shared that the 4 million long-term undocumented individuals are more likely to live with U.S. children (38 percent), in 2012. Approximately 2.1 million unauthorized-immigrant adults (30 percent) live with U.S. born children, whether they're adult or minors.