Washington (CNN) -- It's becoming a familiar story and a welcome one: Violent crime continues to decline.
FBI figures released Monday show overall violent crime in the United States during 2010 declined 5.5% compared with the previous year. That's slightly more than the 5.3% decline the FBI found in its report for 2009.
The report for 2010 released Monday shows murders declined 4.4%, rapes dropped 4.2%, robberies were down 9.5%, and aggravated assaults were down 3.6%.
Non-violent property crimes also declined, falling 2.8%.
The report, while labeled "preliminary," is viewed by the FBI and Justice Department as a very strong indicator of what the final figures will be when released this fall.
The FBI compiles crime reports from more than 13,000 law enforcement agencies across the country, but does not offer explanations or theories for the figures.
Crime declined by lesser amounts in previous years. Violent incidents were down 1.9% in 2008 and 0.7% in 2007.
Criminologists have attributed declines in recent years to an aging population, government anti-crime programs, stiffer sentences, and incarceration policies that include transition and release programs.
Criminologists contacted by CNN say the nation's recent economic difficulties do not appear to have had much of an impact on the crime rate.
The FBI noted some geographical differences in crime last year.
While murder nationally declined, it was up 8.3% in the Northeast. The South had the largest overall drop in violent crime, down 7.5%.