Silver Book Fact
Half of those with persistent pain report severe daily pain–rated as a 7 on a scale of 0 to 10.
Johannes, Catherine B, T Kim Le, Xiaolei Zhou, Joseph A Johnston, and Robert H Dworkin. The Prevalence of Chronic Pain in United States Adults: Results of an Internet-based survey. Journal of Pain. 2010; 11(11): 1230-9. http://www.ncbi.nlm.nih.gov/pubmed/20797916