WASHINGTON - Crime in the United States dropped dramatically in 2009, bucking a historical trend that links rising crime rates to economic woes. Property crimes and violent offenses each declined about 5 percent, the FBI said Monday, citing reports from law enforcement coast to coast.

It was the third straight year of declines, and the 2009 drops were even steeper than those of 2007 and 2008, despite the recession.

There were words of caution from experts.

"It's fabulous news, but I would draw an analogy to global warming: Even if you believe the long-term trend is increasing temperatures, it doesn't mean you can't have a cold year," said Jonathan P. Caulkins, a professor of public policy at Carnegie Mellon University's Heinz College.

Last year's decline was 5.5 percent for violent crime, including 7.2 percent for murders. Property crime was down 4.9 percent, the seventh consecutive drop for that category. Violent crime dropped 0.7 percent in 2007 and 1.9 percent in 2008; for property crime, the previous declines were 1.4 percent in 2007 and 0.8 percent in 2008.

Philadelphia's crime also fell in 2009, with drops that exceeded the national averages. Violent crime in the city was down 7.7 percent, from 20,771 reported incidents in 2008 to 19,163 last year. Property crimes fell 10.7 percent, from 62,580 to 55,888, according to the FBI statistics.

Earlier this year, Mayor Nutter and city police officials trumpeted a two-year drop that saw violent crime in Philadelphia fall nearly 11 percent from 2007. Homicides over the two-year period dropped 22 percent.

From 2008 to 2009, homicides in Philadelphia fell 8.8 percent, according to the FBI statistics.

So far in 2010, Philadelphians have been killing one another at a rate similar to last year. As of Monday, the city had logged 110 homicides, compared with 109 at this time in 2009, according to the Police Department's website.

Long term, said Northeastern University criminology professor James Alan Fox, "there is a connection between an economic downturn and crime: Budget cuts create significant challenges in keeping crime rates low. We have increasing numbers of at-risk youth in the population, and they need services."

The nation's jobless rate hit 10.2 percent in October, reaching double digits for the first time in 26 years. The rate was 9.9 percent last month.

In Phoenix, where property crime declined more than 20 percent, "we thought our property crimes during a recession would probably go up," said Sgt. Trent Crump, a police spokesman. Homicides in Phoenix were down more than 25 percent. Crump attributed the drop in crime to a department focus on getting more officers on the street, targeting repeat offenders, and forming partnerships with community leaders.

Experts offered a range of factors that might have contributed to the drop in reported crimes.

In the past, increases during economic downturns have tended to correspond to street-level drug activity, such as the crack cocaine epidemic during the economic decline of the late 1980s and early 1990s, said Richard Rosenfeld, professor of criminology at the University of Missouri in St. Louis.

But this time, "we're not seeing - at least as yet - comparable increases in drug-market activity," Rosenfeld said.

Fox said the criminal justice system had done a good job of dealing with violence among at-risk youth, and said police departments had better technology and other ways to gather information so that law enforcement resources are used more effectively to investigate crime and apprehend offenders.

Washington, D.C., Assistant Police Chief Peter Newsham said the presence of video surveillance cameras and other technology made it "a lot more difficult to get away with" property crime.

The FBI collected the crime data from more than 13,000 law enforcement agencies. The preliminary numbers will be updated later this year.

Read the FBI crime report for 2009 via http://go.philly.com/fbidataEndText

Inquirer staff writer Troy Graham contributed to this article.