The nation's crime rate last year held steady at the lowest levels since the government began surveying crime victims in 1973, the Justice Department reported yesterday.

The study was the latest contribution to a decade-long trend in which violent crime as measured by victim surveys has fallen by 55 percent and property crime by 49 percent. That has included a 14 percent drop in violent crime from 2000-01 to 2002-03.

"The rates are the lowest experienced in the last 30 years," Justice Department statistician Shannan Catalona said in the report. "Crime rates have stabilized."

The 2003 rate for violent crime -- assault, sexual assault and armed robbery -- stood at 22.6 victims for every 1,000 people ages 12 and older. That amounts to about one violent crime victim for every 44 U.S. residents.

By comparison, there were 23 violent crime victims per 1,000 people in 2002. In 1993, the violent crime rate was 50 per 1,000 people, or about one in every 20 people.

Murder is not counted because the Bureau of Justice Statistics study is based on statements by crime victims. In a separate report based on preliminary police data, the FBI found a 1.3 percent increase in murders between 2002 and 2003 -- from 16,200 to about 16,420.

The new survey put the rate for property crimes of burglary, theft and motor vehicle theft in 2003 at 163 for every 1,000 people, compared with 159 the year before. The slight increase was not considered statistically significant.

A decade ago, there were about 319 property crimes per 1,000 people, the study said.

There are numerous possible explanations for the sustained decrease in crime. But experts say the fact that crime rates have leveled off confounds earlier studies that attributed it to such things as a more mature, less violent drug trade or police tactics that focus on high-crime areas.

James Lynch, professor at American University's Department of Justice, Law and Society, said the reason that crime is down so broadly is difficult to pinpoint.

Two recent possibilities, he said, are a prison population at a record 2.1 million and the terrorism fight's deterrent effect on more routine street crime.

The low crime rate also has made the problem much less of an issue in national political campaigns. It is almost never mentioned in campaign speeches by President Bush or Democrat John F. Kerry, and fewer people than in past years now list crime as a top concern in opinion polls.