The median age declined in seven states between 2012 and 2013, including five in the Great Plains, according to U.S. Census Bureau estimates released today. In contrast, the median age for the U.S. as a whole ticked up from 37.5 years to 37.6 years. These estimates examine population changes among groups by age, sex, race and Hispanic origin nationally, as well as all states and counties, between April 1, 2010, and July 1, 2013.

"We're seeing the demographic impact of two booms," Census Bureau Director John Thompson said. "The population in the Great Plains energy boom states is becoming younger and more male as workers move in seeking employment in the oil and gas industry, while the U.S. as a whole continues to age as the youngest of the baby boom generation enters their 50s."

The largest decline in the nation was in North Dakota, with a decline of 0.6 years between 2012 and 2013. The median age in four other Great Plains states — Montana, Wyoming,South Dakota and Oklahoma — also dropped. Alaska and Hawaii also saw a decline in median age. (See Table 1.) In addition, the median age fell in 403 of the nation's 3,143 counties, many of which were in the Great Plains. Williams, N.D., the center of the Bakken shale energy boom, led the nation with a decline of 1.6 years. Next to Alaska, North Dakota had a heavier concentration of males (51.1 percent of the total population) than any other state.

The nation as a whole grew older as the oldest baby boomers became seniors. The nation's 65-and-older population surged to 44.7 million in 2013, up 3.6 percent from 2012. By comparison, the population younger than 65 grew by only 0.3 percent.

These statistics released today also include population estimates for Puerto Rico and its municipios by age and sex.

Our nation is a study in contrasts when it comes to local age structure. There was a more than 42-year difference in the median ages of the county with the highest median age — Sumter, Fla., at 65.5 — and the county with the youngest median age — Madison, Idaho, at 23.1.

A More Diverse Nation

Non-Hispanic, single-race whites remained the nation's largest group with a population of 197.8 million. The total of all other groups was 118.3 million, or 37.4 percent of the population. Non-Hispanic single-race whites made up 52.4 percent of the population under 18.

Asians were the fastest-growing group from 2012 to 2013, though that distinction has alternated between Asians and Hispanics over the years. The Asian population increased by almost 2.9 percent to 19.4 million, an increase of about 554,000 people. Hispanics remained the second largest group overall, growing by 2.1 percent (or more than 1.1 million) to slightly more than 54 million. Hispanics were 17.1 percent of the total population in 2013, up about 0.2 percentage points from 2012. The primary driver of Asian population growth in 2013 was international migration, accounting for 61 percent of the total Asian population change in the last year. Hispanic population growth, on the other hand, was fueled primarily by natural increase (births minus deaths), which accounted for about 78 percent of the total Hispanic population change.

Following Asians in rate of growth were Native Hawaiians and Other Pacific Islanders (increasing 2.3 percent to just over 1.4 million), American Indians and Alaska Natives (increasing 1.5 percent to slightly more than 6.4 million) and blacks or African-Americans (increasing 1.2 percent to 45 million).

The non-Hispanic white alone population was the only group to have natural decrease (more deaths than births) from 2012 to 2013. However, due to migration, its population rose 0.1 percent from 2012 to 2013, reaching 197.8 million. Because of its slow rate of growth relative to other groups, its share of the total population declined from 63.0 percent to 62.6 percent over the period.

Highlights for each race group and Hispanics, age groups and both sexes at the national, state and county levels follow. For Hispanics and each of the race groups listed below (except for American Indians and Alaska Natives), their populations rose at a faster rate from 2012 to 2013 in North Dakota than in any other state.

For the full release, please go to http://www.census.gov/newsroom/releases/archives/population/cb14-118.html