Elizabeth,

According to the most recent Bureau of Judicial Statistics report I could find, 5% of state and federal prisoners in 2013 were not U.S. citizens.  That's different from what utilitas stated of course.  He has conflated non-citizen and illegal alien.  They are not the same.  There are tens of millions of non-citizens who are in this country legally.  Also, some states included in the report define non-citizens as those born outside the U.S. ... regardless of current citizenship status.

So, the bottom line is that utilitas has misstated the facts.  Not all the non-citizen prisoners in the BOJ report are in this country illegally.  Some of the 73,000 (73,665 to be exact) are here legally and some are even U.S. citizens.