There are a lot of old people. In the 1990 census, patients over the age of 65 comprised 12% of the United States population, or 30,000,000 people. That grew modestly, to 12.5%, by 2000. However, based on the United States population of 301,165,915 as of today, that amounts to 38 million individuals. It should come as no surprise, therefore, that health care for the elderly consumes 5% of the United States gross domestic product.¹