Homicides are easy to document, and those are the stats used in the graphs. It's other crimes that are difficult to compare.
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.
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.