Two very interesting newspaper articles about the same thing, but each has a different focus.
After New York and California, Massachusetts has more artists than other states in the US. Read the Boston Globe's article, "Study finds Mass. draws artists," by Geoff Edgers, June 12, 2008.
Or, read the New York Times' article, about the Arts in different US states, "A 21st-Century Profile: Art for Art’s Sake, and for the U.S. Economy, Too," by Sam Roberts, June 12, 2008.
This is the National Endowment for the Arts' New
Artists In The Workforce Study press release.
And here is the NEA's actual Artists In the Workforce study, in PDF format. It's 150 pages long, so it might be slow to load.