Silver Book Fact
The annual economic cost of persistent pain in the U.S. is at least $560 to $635 billion (in 2010$).
Gaskin D, Richard P. The Economic Costs of Pain in the United States. J Pain. 2012; 13(8): 715-24. http://www.jpain.org/article/S1526-5900(12)00559-7/abstract