Updated

The number of police officers nationwide who were killed by criminals while on the job in 2005 dipped slightly from a year earlier, FBI data released Monday show.

An estimated 1,800 fewer cops were assaulted during the same time period — the lowest total since 2001.

Nearly all of the officers killed — 55 in 2005, down from 57 in 2004 — worked for city police departments, according to the FBI's annual report.

All but one of the slain officers were men, who on average were 37 years old with a decade of law enforcement service. More than half of them — 28 — were killed in a swath of southern states stretching from Delaware to Texas. Forty-seven of the officers were white; eight were black.

Traffic duty proved to be the most lethal assignment for the officers, the report shows.

Fifteen cops were killed during traffic pursuits or on traffic stops, compared with eight slain while making arrests and another eight who were ambushed. The rest of the killings came while breaking up family quarrels, investigating suspicious activity, transporting prisoners and other duties.

Additionally, 67 officers were accidentally killed on duty last year, down from 82 in 2004.

Another 57,546 police officers were assaulted while on the job in 2005, down from 59,373 in 2004. The largest number of assaults came in the early morning hours, from midnight to 2 a.m., while police were breaking up bar fights, family quarrels and other disturbances.

The FBI's assault data were collected from 10,032 law enforcement agencies nationwide, serving 75 percent of the population.