ScienceDaily (Mar. 16, 2011) — A recent study from North Carolina State University shows that while the number of visits to state parks across the country has grown, fund support for park operations has been significantly reduced. The reduction in funding during a time of park growth endangers the more than $20 billion in economic impact that state parks have on the nation's economy.
http://www.sciencedaily.com/releases/2011/03/110316153125.htm