Not sure what to make of it either. It's kind of a lame chart. Does it mean there have been more JHs if the bar is above the line, or less, and is that necessarily a good thing? It could just be that some of those states have had more or less homicides in general?
I know it's kind of off topic, but I do find this map rather interesting;
http://chartsbin.com/view/1454
Dave