The median age of Americans is 37.2

The U.S. Census Bureau released today a 2010 Census brief on our nation's changing age and sex composition that shows the nation grew older while the male population grew faster than the female population over the last decade.

According to Age and Sex Composition: 2010, the median age of Americans is now 37.2, with seven states recording a median age of 40 or older. The brief also shows the male population grew 9.9 percent between 2000 and 2010, while the female population grew 9.5 percent. Of the total 2010 Census population, 157.0 million people were female (50.8 percent) and 151.8 million were male (49.2 percent).

Selected Age Categories

Between 2000 and 2010, the population 45 to 64 years old grew 31.5 percent to 81.5 million. This age group now makes up 26.4 percent of the total U.S. population. The large growth among 45- to 64-year-olds is primarily because of the aging of the baby boom population. The 65-and-older population also grew faster than most younger population groups at a rate of 15.1 percent to 40.3 million people, or 13.0 percent of the total population.

For those under 18 and between the ages of 18 and 44, growth rates were much slower. Between 2000 and 2010, the number of people under 18 grew 2.6 percent to 74.2 million people, comprising 24.0 percent of the total population. The 18 to 44 age group grew at an even slower rate of 0.6 percent to 112.8 million, comprising 36.5 percent of the population.

Median Age

In 2010, the median age increased to 37.2 from 35.3 in 2000, with the proportion of older Americans increasing. The 1.9-year increase between 2000 and 2010 was a more modest increase than the 2.4-year increase in median age that occurred between 1990 and 2000. The aging of the baby boom population, along with stabilizing birth rates and longer life expectancy, have contributed to the increase in median age.

Sex Ratios

In 2010, there were 96.7 males for every 100 females in the United States, representing an increase from 2000 when the male-to-female ratio was 96.3 males for every 100 females. The increase in the population of older males was notable over the last decade, with males between the ages of 60 and 74 increasing by 35.2 percent, while females in the same age group increased by just 29.2 percent. This increase in the male population relative to the female population for those 60 and over has led to a notable increase in the sex ratio among this age group – potentially because of the narrowing gap in mortality between older men and women.

Geographic Distribution

In the 2010 Census, seven states had a median age of 40 or older: Maine (42.7), Vermont (41.5), West Virginia (41.3), New Hampshire (41.1), Florida (40.7), Pennsylvania (40.1) and Connecticut (40.0). In both 1990 and 2000, West Virginia and Florida had the highest median age of all states. Maine overtook West Virginia and Florida as the state with the highest median age in 2010, while Utah remained the state with the lowest median age.

States with the lowest median age (excluding the District of Columbia) remained the same as they were in 2000: Utah (29.2), Texas (33.6), Alaska (33.8) and Idaho (34.6). Utah had the highest percentage of population under age 18 (31.5 percent) and remained the only state with a median age under 30.

All states experienced an increase in median age when compared with 2000 – a further indication of population aging. However, the District of Columbia experienced a decrease in median age, declining from 34.6 to 33.8. In the District of Columbia, almost half (48.6 percent) of the 2010 Census population was between the ages of 18 and 44.

Regionally, the Northeast recorded the oldest median age at 39.2, followed by the Midwest at 37.7, the South at 37.0 and the West at 35.6. In the West, 24.9 percent of people were under the age of 18 and 37.8 percent of people were between the ages of 18 and 44. The Northeast recorded the largest percentages of people in the age groups 45 to 64, and 65 and over (27.7 percent and 14.1 percent, respectively).

All four regions of the United States had a sex ratio of less than 100 in 2010, indicating more females than males nationwide. The Northeast had the lowest sex ratio (94.5 males per 100 females), followed by the South (96.1), the Midwest (96.8) and the West (99.3).