The Medicare Part D prescription drug benefit, subsidizing drug benefits for Medicare beneficiaries, was born out of the Medicare Modernization Act of 2003. President George W. Bush signed the legislation into law, launching a major new entitlement program. The standard benefit requires payment of a deductible and then co-insurance for drug costs up to an initial coverage limit, a threshold that changes over time. Once this initial coverage limit is reached, the beneficiary must pay the full cost of prescription drugs until the total out-of-pocket expenses reach a much larger amount, excluding premiums. This gap between the initial coverage limit and the catastrophic coverage limit is commonly known as the “doughnut hole.” One provision of the Patient Protection and Affordable Care Act of 2010 gradually shrinks the doughnut hole over time. Enrollment in Part D as of April 2010 was estimated at 27.6 million beneficiaries. In 2010, there were more than 1,500 stand-alone Part D plans available, down from nearly 1,700 plans in 2009. One estimate of the program's costs from 2009 to 2018 was $727 billion.