"In 2005, 6.4 million households, representing 5.5% of all households in the United States, discovered that at least one member experienced one or more types of identity theft. This is the first full year of data on identity theft available from the National Crime Victimization Survey (NCVS). Questions on identity theft were first added to the NCVS in July 2004."
U.S. Dept. of Justice, Office of Justice Programs: http://www.ojp.usdoj.gov/