The length of time that illegal immigrants stay in the Untied States has spiked drastically over the last decade, according to a recent Pew Research Center study [emphasis added]:
Among the nation’s 10.4 million unauthorized adults, a shrinking share have been in the country for less than five years—15% in 2012, compared with 38% in 2000. A rising share have lived in the U.S. for a decade or more—62% in 2012, compared with 35% in 2000. About a fifth (21%) had been in the U.S. for two decades or more as of 2012.
The rise of long-term residents has been encouraged by laws in the United States that make it easier for aliens to blend in and assimilate into American society. These include allowing illegal immigrants to obtain temporary drivers licenses, fly (probably with less hassle from TSA than most legal residents have), and to go to public school on your taxpayer dollar.
In fact, the number of long-term illegal residents has now acutely outnumbered the number of those who remain in the country for only a short-period of time.
With laws that do little more than encourage aliens to stay, and with an immigration court system that is underfunded and grossly back-logged with cases, it is no wonder that these illegal foreigners are finding it easy to lengthen their stay in the United States.