The nation's murder rate declined last year for the first time in four years, dropping to the lowest level in 40 years. Experts said local rather than national trends were mostly responsible.

The rates for all seven major crimes were down and the overall violent crime rate reached a 30-year low, according to the FBI's annual compilation of crimes reported to the police.

There were 391 fewer murders nationwide in 2004 than the year before. The total of 16,137 worked out to 5.5 murders for every 100,000 people.

That's a decline of 3.3 percent from 2003 and the lowest murder rate since 1965, when it was 5.1.

"The declines are relatively small compared to larger, steady drops in the 1990s, and the results are by no means the same across the country," said Professor Alfred Blumstein of Carnegie-Mellon University (search) in Pittsburgh.

"We're not seeing important national trends like the shrinking of crack markets in the 1990s," Blumstein added. "These are responses to local situations, changes in local drug markets and shifts in gangs."

Blumstein said Chicago with a decline of 150 murders and Washington, D.C., with a decline of 50 accounted for 51 percent of the net nationwide drop. St. Louis (search), on the other hand, saw an increase of 39 murders.

Of 19 large cities with more than 100 murders apiece in 2003, 13 had declines in 2004 while six recorded increases, Blumstein said.

"Most of these changes result from local conditions or random variation," said Professor James Alan Fox of Northeastern University in Boston (search). The fastest growing population segment is still people over age 50, who commit few violent crimes, so that should produce some decline in murder, but "it's not a rosy picture all around the country."

"The best news is that there's no national increase despite reasons — like economic conditions — why it could rise," Fox added. Other reasons he cited were growing gang violence in some cities, local law enforcement budget cuts and a shift of federal law enforcement aid from local police hiring to homeland security.

"It would be easy to look at these numbers and get too complacent about crime," Fox said. "That would be a mistake."

The four major violent crimes — murder, rape, robbery and aggravated assaults — declined from 1.38 million in 2003 to 1.37 million in 2004. That produced a 2.2 percent drop in the violent crime rate to 465.5 crimes per 100,000 people — the lowest since 1974, when it was 461.1.

The three major property crimes — burglary, auto theft and larceny-theft — declined from 10.42 million to 10.33 million in 2004. That pulled the property crime rate down 2.1 percent to 3,517.1 crimes per 100,000 people. These crimes produced an estimated loss of $16.1 billion, down 5 percent from 2003.

Chicago officials and academics have credited that city's murder decline to police targeting of gangs, drugs and guns. Blumstein said a program that recruited "ex-offenders to go out into the community to gain intelligence" had helped police flood neighborhoods where trouble might be brewing. By contrast, he said, St. Louis' increase might have been a return to normal trends after a better-than-average year.

The South — with 36 percent of the nation's population but 43 percent of its murders — saw larger murder declines than any other region. The Southern regional murder rate declined 5 percent to 6.6 per 100,000.

Blumstein said that might have been driven by declines in Atlanta; Memphis, Tenn., and New Orleans, each with over 100 murders in 2003, or "it might mean the South is becoming more like the rest of the country."

Rape was the only one of the seven crimes to show a numerical increase, up 0.8 percent to 94,635 offenses, but the rate of rape declined 0.2 percent to 32.2 per 100,000 people. Lynn Parish of the Rape, Abuse & Incest Network, a national anti-sexual assault group, said Justice Department studies show the incidence of rape, whether reported to police or not, has been declining over 30 years while reporting of rape to police has climbed for a decade.

The FBI data were compiled from reports to more than 17,000 law enforcement agencies, representing 94.2 percent of the nation's population. The Justice Department has found that barely half of all violent crimes and less than 40 percent of property crimes are reported to the police, but its surveys of crime victims, which also track unreported crimes, show trends similar to those among the reported crimes tracked by the FBI.