It was the first year-to-year increase for violent crime since 1993, marking the end of a long string of declines. Violent crime fell by 65 percent since 1993, from 16.8 million to 5.8 million last year.
According to the U.S. Bureau of Justice Statistics' annual national crime victimization survey, the size of the percentage increases in both violent crime and property crime for last year was driven in large part by the historically low levels seen in 2010.
The increase in violent crime was the result of an upward swing in assaults, which rose 22 percent, from 4 million in 2010 to 5 million last year. But the incidence of rape, sexual assault and robbery remained largely unchanged, as did serious violent crime involving weapons or injury
"While it's cause for concern, I would caution against forecasting future crime trends based on a one-year fluctuation," said Chris Melde, an assistant professor at Michigan State University's school of criminal justice.
"You can have percentage changes that seem quite large, but unless you put them in a longer-term perspective you can sometimes misinterpret the overall seriousness of the problem," Melde added.
The increases in violent crime experienced by whites, Hispanics, younger people and men accounted for the majority of the increase in violent crime.
In the latest survey, property crime was up for the first time in a decade, from 15.4 million in 2010 to 17 million last year. Household burglaries rose 14 percent, from 3.2 million to 3.6 million. The number of thefts jumped by 10 percent, from 11.6 million to 12.8 million.
The victimization figures are based on surveys by the Census Bureau of a large sample of people in order to gather data from those who are victims of crime. They are considered the government's most comprehensive crime statistics because they count both crimes that never are reported to the police as well as those reported.
Last May, the FBI's preliminary crime report for 2011, which counts only crimes reported to police, concluded that crime dropped again last year, down 4 percent for violent crime and 3.7 percent for property crime. The declines slowed in the second half of last year, a sign to academic experts that the many years of lowering crime levels might be nearing an end. Historically, less than half of all crimes, including violent crimes, are reported to police.