ORLANDO, Fla. (AP) — America is aging.

Data released by the U.S. Census Bureau on Thursday shows the median age in the U.S. increased by a year to 38.2 years from 2010 to 2018.

If there’s someone to blame, it’s the baby boomers. Many in that group of Americans born between the end of World War Two and the Beatles’ American invasion in 1964 have been hitting the retirement mark in the past eight years.

The only state whose median age got younger was North Dakota, which has undergone a population boom driven by growth in the energy sector. The median age went from 37 years in 2010 to 35.2 years in 2018.