According to
CNN, the number of police attacked or threatened on the job was 306 per thousand, while the number for private security guards was 218 per thousand. According to the
National Traumatic Occupational Fatalities (NTOF) Surveillance System sheriffs and bailiffs are murdered on the job at twice the rate as private security guards, but at half the rate of taxi drivers and chauffeurs (who are sometimes lucky to even get tipped). Police and detectives (public service) were murdered on the job at a similar rate to private security guards.
According to CNN, the number of police attacked or threatened on the job was 306 per thousand... The findings were part of a newly-released report based on surveys of 45,000 households every six months between 1992 and 1996.
Violence was defined as anything from a mere threat of violence to rape to assault to homicide.
You are comparing apples to oranges. The U.S. Department of Labor Statistics reports work-related fatalities. The questionable "survey" you reference lumps minor threats (these days "you are a jerk" can be construed as a threat) together with homicide.
Not a very scientific survey. I will stick with the U.S. Department of Labor Statitics numbers, thank you.