Retail prescription drug expenditures were estimated to account for about 12 percent of total personal health care service spending in the United States in 2015, up from about 7 percent through the 1990s. Much of this growth was driven by use of expensive brand-name drugs, but price increases have been reported for some generic drugs as well. Prior GAO reports have identified multiple reasons for drug price increases, including limited competition. Experts have questioned whether consolidation among drug companies could reduce competition and R&D investment in new drugs...