WASHINGTON — The nation's crime rate dropped an additional 5 percent last year, continuing a 20-year trend that has cut the incidence of major crimes nearly in half, according to the FBI's crime statistics.
Crime experts have cited several possible explanations, including better policing, a swelling of the prison population, the decline of the crack cocaine epidemic and an aging population. Regardless, crime fell sharply during the 1990s and has declined gradually since then.
Last year, the rate of murders and manslaughter was 5 per 100,000 Americans, down from 9.8 in 1991. Overall, the rate of violent crimes fell more than a third during that time, from 758 per 100,000 in 1991 to 429 last year. This number includes homicides, rapes, robberies and assaults.
Common property crimes also declined sharply over the two decades. For example, the FBI counted 1,661,000 thefts of motor vehicles in 1991. Last year, it counted 794,616. This was a drop of 164,000 vehicle thefts from 2008.
"This is good news. It should get more attention," said John Conklin, a Tufts University sociologist who has written widely on crime and its causes.
He said the recent declines in crime contradict predictions that a bad economy and high unemployment would lead to an increase in thefts, robberies and other crimes. Conklin studied the steep decline in crime rates in the 1990s and concluded the most important cause was the increase in the prison population.
"If you lock up a lot more people, you will probably see reduced crime," he said. "That's doesn't necessarily mean I recommend a 'lock-them-up' policy. We have the world's highest rate of incarceration."
The FBI released its final crime statistics for 2009 on Monday. The report highlighted the across-the-board drop in crime between 2008 and 2009.
Robberies declined by 8 percent, murders by 7.3 percent, aggravated assaults by 4.2 percent and forcible rapes by 2.6 percent. The number of property crimes fell by 4.6 percent, including the 17 percent drop in motor vehicle thefts.
The FBI also breaks down its data by four regions of the nation and reported that property and violent crimes are highest in the South and lowest in the Northeast.