Michigan is No. 1! At getting old. That’s not good news.

Michigan’s battle of the birthdays continues, as more than one-quarter of the state’s counties have a median age that’s eligible for AARP membership.

U.S. Census data released Thursday show that 21 of Michigan’s 83 counties have a median age of 50 years old or older, the highest in the nation.Next closet was Montana with 13 (out of 56 counties) and Texas with 12 (out of 254), according to estimates released Thursday morning by the U.S. Census.

Overall, Michigan’s median age of 39.8 years ranks it the 12th oldest in the country. As recently as 1990, Michigan’s median age was younger than the nation.

But huge areas of northern Michigan are pulling that number up, raising questions about economic vitality in areas where far more people are closer to retirement than their first day of work.

The changes have been apparent for years – there are fewer and fewer obstetric doctors because there are fewer and fewer births in many parts of the state. In a number of counties, death outnumber births.

Overall, the nation is aging as well. But Michigan’s rise has been marked –  only two counties got younger from 2010 to 2018 and those were home to major colleges which attract young students, noted Kurt Metzger, a Metro Detroit demographer and mayor of Pleasant Ridge, who has studied population trends for decades.

“While an older population is great for health care and related retirement-based businesses, it is not one that will drive entrepreneurship and associated business growth,” Metzger wrote in a summary of his observations about the changes, revealed in the Thursday release of new census data.

Economists have warned that the state faces a worker shortage, with retiring workers not replaced by younger ones.

Metzger said only nine Michigan counties had a median age less than the national average of 38.2 years. He attributed that, in part, to the colleges and universities in Kent, Ottawa, Kalamazoo, Isabella, Houghton, Mecosta, Washtenaw, and Ingham counties.

The only other county below the national average is Wayne, home to Detroit. Although the county it has Wayne State and other colleges and universities, it also has the highest share of people of color -- 50 percent -- who tend to be younger than the white, non-Hispanic population, Metzger said.