"During 2009, the number of suspects arrested for a federal offense reached a record level of 183,986 suspects--up from 140,200 in 2005. Since 1995, the number of suspects arrested by federal law enforcement has more than doubled. Stepped-up immigration enforcement along the U.S.-Mexico border has had a significant influence on the nature and outcomes of criminal cases handled in the federal justice system. Between 2005 and 2009, immigration arrests increased at an annual average rate of 23%. Immigration offenses (46%) were the most common of all arrest offenses in 2009, followed by drug (17%) and supervision (13%) violations."
Bureau of Justice Statistics: http://bjs.ojp.usdoj.gov/