The Number of Centenarians in the United States on January 1, 1990, 2000, AND 2010 Based on Improved Medicare Data

The title of the conference that this paper was written for was ‘‘Living to 100 and Beyond.’’ People who have achieved this feat are called centenarians, and a small literature has developed from population scientists interested in measuring the size of the centenarian population. Two assertions of a general nature that appear in this literature are examined in our paper. The first is an assertion by the esteemed Finnish demographer, recently deceased, Väinö Kannisto, which he based on data from about 20 developed countries for years around 1985, that the centenarian population in a developed country at that time was about one-twentieth of 1%— somewhat more or somewhat less—of its population age 75 and over (Kannisto 1990). Kannisto then used this relationship—after noting that the latest official U.S. census count of centenarians was unsatisfactory—to estimate that the number of U.S. centenarians in 1985 was about 5,500. He also estimated that the number of centenarians in the entire world at that time was about 30,000. The second is the assertion by the noted demographers James Vaupel of the Max Planck Institute on Demographic Research in Germany and Bernard Jeune of the University of South Denmark in a chapter in their monograph on extreme old age (Vaupel and Jeune 1995) that the number of persons in a country achieving the century mark in a given year has been about double the number achieving that milestone 10 years