I always liked to point "we live in a dangerous world now" folks here: http://www.vrc.crim.cam.ac.uk/vrcresearch/paperdownload/manu... - in particular the graph on the third page.
Find an old source saying "Blimey, we hath hadd 200 of thee black cryme of murder thys annus!" and cross-reference it against recorded population at the time, and there's your homicide rate.