In fiscal year 2000, 16,495 persons were referred to U.S. attorneys for a suspected immigration offense as the most serious charge. This represents a record high in a rising trend following passage of the Illegal Immigration Reform and Immigrant Responsibility Act of 1996. In addition to immigration offenses, U.S. attorneys prosecuted an increased number of noncitizens charged with other offenses -- particularly drug trafficking offenses. Between 1985 and 2000 the number of noncitizens prosecuted by U.S. attorneys for drug trafficking offenses increased from 1,799 to 7,803. The 1996 act authorized increases in law enforcement by the U.S. Immigration and Naturalization Service (INS). Following enactment, the number of INS law enforcement officers increased from 12,403 to 17,654. The Border Patrol received almost two-thirds of the additional officers. About 75% of the increase in referrals to U.S. attorneys for immigration offenses between 1996 and 2000 was observed in the five States that received the greatest number of new INS officers.