Sumter County in Florida, home to The Villages retirement community, once again is the county with the highest median age in the country, according to new U.S. Census Bureau population estimates released Thursday.

The county also experienced the highest increase in median age. Sumter County’s median age jumped from 49.2 years in 2000 to 67.1 years in 2016, an increase of 17.9 years. Last year, the government reported the county’s 2015 median age as 66.6 years, the highest in the country at that time, too.

The median age is the age at which half of the population is younger and half is older.

Sumter was one of two counties with median ages of more than 60 years in 2016. Its median age was 67.1 years, and the median age in Catron County, NM, was 60.5 years. But 66.7% of the nation’s counties saw an increase in median age last year, according to the Census Bureau.

In fact, between 2000 and 2016, 95.2% of all counties experienced increases in median age (see graphic below). Since 2000, 56 counties showed a median age increase of 10 years or more.

One example cited by the bureau was Noble, a small county in Southeast Ohio. The county has experienced net outmigration and deaths almost equal to the rate of births. Its 2016 median age of 51.5 years is 16 years higher than what it was in 2000 (35.5 years).

Across the country

Overall, the country’s population has a distinctly older age profile than it did 16 years ago, according to the newly released data. The nation’s median age increased from 35.3 years on April 1, 2000, to 37.9 years on July 1, 2016.

And that profile is only going to get older as baby boomers age and younger adults delay having children.

“The baby boom generation is largely responsible for this trend,” Peter Borsella, a demographer in the bureau’s Population Division, said in a statement. “Baby boomers began turning 65 in 2011 and will continue to do so for many years to come.”

The number of people aged 65 or more years grew from 35 million in 2000 to 49.2 million in 2016, accounting for 12.4% and 15.2% of the total population in those years, respectively.

The median age is increasing in most areas of the country, bureau statistics revealed.

For 2016, every state experienced either an increase or had the same median age as a year earlier. At 44.6 years, the median age in Maine is the highest in the nation. New Hampshire’s median age of 43 years is the next highest, followed by Vermont at 42.7 years. (See the table above for additional information.)

The Nation's Median Age Continues to Rise[Source: U.S. Census Bureau]