“Expenditures for the Top Five Therapeutic Classes of Outpatient Prescription Drugs, Medicare Beneficiaries, Age 65 and Older, U.S. Civilian Noninstitutionalized Population, 2009,” by Anita Soni (Statistical Brief No. 363, March 2012, .pdf and HTML format, 6p.).
meps.ahrq.gov/mepsweb/data_stats/Pub_ProdResults_Details.jsp?pt=Statistical+Brief&opt=2&id=1046
