There is some coverage of this number, which varies quite a bit from year to year. The number being shown is 33, but that appears to include one accident. The trend is down, though not as much as the homicide rate in general. It is clear that the number of citizen owned guns is not linked to the number of police killed with guns. While the number of guns in the hands of the public has soared, and the number of people legally carrying firearms has skyrocketed, crime is down, homicides are down, and then number of police murdered...