The country’s only county in which a majority of the population is aged 65 or more years remains Sumter, FL, according to new U.S. Census Bureau population estimates released Thursday. There, 54.8% of residents had reached retirement age in 2015, up from 53% in 2014, when it also held this distinction.

The new estimates, based on 2015 data, consider counties with at least 1,000 residents. Part of the nation’s fastest growing metro area (The Villages), Sumter County had a median age of 66.6 years on July 1, 2015.

“As the nation’s 65-and-over population grows, other counties with retirement communities like The Villages will get closer to this threshold,” said Jason Devine, the bureau’s assistant division chief for population estimates and projections.

The nation’s 65-and-older population increased from 46.2 million in 2014 to 47.8 million in 2015, according to the Census Bureau. This group continues to show rapid percentage growth, even as baby boomers and older generation groups that make up this age group decline in population.

Among counties with a population of 1,000 or more, only two nationwide had a median age of 60 or more years in 2015. In addition to Sumter County, the other was Catron, NM (60.1 years). In all, 160 counties had a median age of 50 or more years. Rounding out the top five oldest were Charlotte, FL (58.4 years); Alcona, MI (57.9 years); and Ontonagon, MI (57.3 years), tied with Jefferson, WA (57.3 years).