WASHINGTON U.S. violent crimes including murders fell 4.4 percent in 2013 to their lowest number since the 1970s, continuing a decades-long downturn, the FBI said on Monday.
The law enforcement agency's annual Crime in the United States report showed the country had an estimated 1.16 million violent crimes last year, the lowest number since 1.09 million were recorded in 1978.
All types of violent crimes were lower, with murder and non-negligent manslaughter off 4.4 percent to 14,196, the lowest figure since 1968. Rape was down 6.3 percent and robbery fell 2.8 percent, the Federal Bureau of Investigation data showed.
James Alan Fox, a criminologist at Northeastern University in Boston, said there was a variety of factors behind the decline in violent crime in recent decades, including the United States having the highest rate of imprisonment in the world.
He said an aging population and improved police tactics also played a role, along with the increased use of security cameras and the pervasive use of phones to take videos.
"It's hard for criminals to do anything without being caught on video," Fox said.
The violent crime rate last year was 367.9 for each 100,000 in population, down 5.1 percent from 2012. The rate has fallen every year since at least 1994, the earliest year for readily accessible FBI data, and the 2013 figure was about half the 1994 rate.
Property crimes fell 4.1 percent to an estimated 8.63 million last year, the 11th straight yearly decline. Losses from property crimes excluding arson were calculated at $16.6 billion, the FBI said.
In an analysis, the non-profit Pew Charitable Trusts said the drop in crime coincided with a decline in the prison population, with the number of U.S. prisoners down 6 percent in 2013 from its peak in 2008.
Thirty-two of the 50 states have seen a drop in crime rates as the rate of imprisonment fell, Pew said.
California notched the largest drop in imprisonment rate over the five-year period, at 15 percent, and crime was down 11 percent. The state has been under court order to reduce prison overcrowding, and voters last week approved an initiative that reduced sentences for some crimes.
(Reporting by Ian Simpson; Editing by Jim Loney and Eric Beech)