In developed countries, persons aged 65 and older depend on a variety of public and employer-provided retirement programs for much of their income. Many retirees supplement benefits from these retirement programs with earnings and asset income while others rely almost entirely on the government retirement programs. The continued aging of national populations is increasing the cost of providing income and medical services to older persons. As a result, reform of Social Security retirement and health care programs is among the most important public choices now facing the countries of Europe and North America.