http://www.google.com/publicdata/explore?ds=a7jenngfc4um7_&ctype=l&strail=false&nselm=h&met_y=personal_income_per_capita&scale_y=log&ind_y=false&rdim=region&ifd

http://www.google.com/publicdata/explore?ds=a7jenngfc4um7_&ctype=l&strail=false&nselm=h&met_y=personal_income_per_capita&scale_y=log&ind_y=false&rdim=region&ifdim=region&tdim=true&tstart=-1272139200000&tend=1284004800000&hl=en&dl=en&uniSize=0.035&iconSize=0.5&icfg http://www.google.com/publicdata/explore?ds=a7jenngfc4um7_&#... This is a log-scale graph, which is what you want in order to compare rates of increase. You can see sort of an inflection point around the early 80s, but I'm not sure if it's significant.