States do not sum to U.S. total. PDP organizations offer plans or benefits packages to the 34 PDP regions which may include one or more states.
PDP organizations can offer more than one plan per contract.
Data do not include territories.
The Medicare Prescription Drug, Improvement, and Modernization Act of 2003 (MMA) added prescription drug coverage to Medicare (Medicare Part D), beginning on January 1, 2006. Medicare's elderly and disabled beneficiaries can enroll in private plans that contract with Medicare to provide the drug benefit. People on Medicare can obtain the Medicare drug benefit through two types of private plans. Beneficiaries can join a prescription drug plan (PDP) for drug coverage only and get their other Medicare benefits through the fee-for-service program, as the majority of people with Medicare currently do. Alternatively they can join a Medicare Advantage (MA) plan, such as an HMO or regional PPO, that covers drugs and all other Medicare benefits. Private plans can operate in one or more of 34 PDP regions and 26 MA regions nationwide.
For more information including details about low-income assistance under the Medicare Drug Benefit, visit Kaiser's Resources on the Medicare Drug Benefit, available at http://www.kff.org/medicare/rxdrugbenefit.cfm.

Benchmark plans are not designated in the territories because low-income beneficiaries residing in the territories are not eligible for the LIS. Instead, the territories receive federal Medicaid funds to provide “wrap-around” Medicare drug coverage for beneficiaries who are dually eligible for Medicare and Medicaid benefits. Other low-income Medicare beneficiaries who have incomes below 150 percent of the federal poverty level, even those who receive partial Medicaid benefits, are not eligible for financial assistance to help with Part D premiums and cost sharing, though they would be eligible if they resided in the 50 states or the District of Columbia. (Mary Ellen Stahlman, “The Medicare Drug Benefit: Update on the Low-Income Subsidy,” Issue Brief No. 833, National Health Policy Forum, July 2009.)

Kaiser Family Foundation/Georgetown/NORC analysis of CMS PDP Landscape Source Files, 2006-2010. Available at: http://www.kff.org/medicare/7986.cfm.

PDPs: Prescription Drug Plans.