In 2000, the U.S. Census Bureau counted 281.4 million people in the United States.¹ Of this number;

• 72.3 million, or 26 percent of the U.S. population, were under age 18;
• 174.1 million, or 62 percent, were age 18 to 64; and
• 35.0 million, or 12 percent, were age 65 and over.

The age groups under 18 years, 18 to 64 years, and 65 years and over experienced similar growth rates over the past decade — 13.7 percent, 13.2 percent, and 12.0 percent, respectively. Median age increased from 32.9 in 1990 to 35.3 in 2000, reflecting a change in age distribution toward the older ages within the age range 18 to 64.²

This report, part of a series that analyzes population and housing data collected from Census 2000, provides a portrait of the age structure of people in the United States. It highlights information about various age groups in the country as a whole, the four regions, states, counties, and places with populations of 100,000 or more. It also includes comparisons with data from the 1990 census.³

A question on age has been asked since the first census of the population in 1790. The Census 2000 age data were derived from a two-part question that was asked of all people. The first part asked for the age of the person, and the second part asked for the date of birth (see Figure 1).

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¹ The text of this report discusses data for the United States, including the 50 states and the District of Columbia. Data for the Commonwealth of Puerto Rico are shown in Table 2 and Figure 6.
² Median age splits the population into halves. One-half of the population is older than the median age and the other half is younger.
³ 1990 populations shown in this report were originally published in 1990 census reports and do not include subsequent revisions resulting from boundary or other changes.