WASHINGTON — The violent crime rate went up 15 percent last year, and the property crime rate rose 12 percent, the government said Thursday, signs that the nation may be seeing the last of the substantial declines in crime of the past two decades.
Last year marked the second year in a row for increases in the crime victimization survey, a report that is based on household interviews.
The 2012 increases were driven by a rise in crimes that were not reported to police, a category frequently involving less-serious offenses. Simple assaults also rose. The rate of property crimes increased due to a rise in theft.
‘‘One year of bad news is something you notice but don’t necessarily draw conclusions about. Two years of bad news suggests it might be time to start worrying,’’ said Carnegie Mellon University professor Jonathan Caulkins.
University of Maryland criminology professor James Lynch said the crime victimization survey, combined with a separate report recently issued by the FBI, suggests that the 20-year trend of dropping crime rates may be approaching an end.
‘‘You’re getting more evidence that this is a change in the trend,’’ said Lynch, a former director of the US Bureau of Justice Statistics, the agency that issued Thursday’s findings.