Not sure I'd base gun control laws on stuff like this. Although Utah, Idaho and Wyoming are doing pretty good. Demographics, law enforcement policies, how statistics are collected...it is tough. Here in Arizona, there is a LOT of violence - within a 2 mile wide corridor following I-19 to Tucson and I-10 from Tucson to west Phoenix. That's due to the flow of drugs. Outside that corridor is pretty safe.
Do that chart by racial demographics, and a different picture will appear...