CBO – Spending Patterns for Prescription Drugs Under Medicare Part D, December 2011: “The centerpiece of the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 (Medicare Modernization Act) was the creation of Medicare Part D, a subsidized pharmaceutical benefit that went into effect in 2006. That additional coverage—which provides outpatient prescription drug insurance to seniors and to people under age 65 with certain disabilities—constituted the most substantial expansion of the Medicare program since its inception in 1965. In 2010, the federal government spent $62.0 billion on Part D, representing 12 percent of total federal spending for Medicare that year.”