Average life expectancy in the United States has increased dramatically over the last century, from just 49 years at the turn of the century to just over 76 years in 1996, the latest year for which such data are available (National Center for Health Statistics, 1997;1998). While earlier gains in life expectancy may be attributed to reductions in infant mortality and the control of infectious diseases, reductions in mortality at the oldest ages are believed to be the major factor responsible for increased life expectancy in recent decades (Vaupel and Jeune, 1995). This has led to an increasing number of people living to extreme old ages, including those reaching age 100 years or above.
This report focuses on the characteristics of those people identified as centenarians in the1990 Census of Population and Housing for the United States. While its purpose is not to provide the definitive answer to the number of people aged 100 or above in 1990, this report does give a range of estimates. In 1990, there were 37,306 people identified as centenarians in the census which is most likely an overstatement of the “true” number of centenarians. Estimates of the number of centenarians in the United States by the Census Bureau and the Social Security Administration (SSA) range from around 28,000 in 1990 to 29,131 at the end of 1991, respectively (Das Gupta, 1999; Kestenbaum, 1998). The uncertainty of the numbers is discussed in the section on data quality which addresses these issues and their effects on both the enumeration and estimation of centenarians in 1990. First, however, we shall examine the characteristics of individuals identified as being aged 100 or above in the 1990 census.