The average age of first-time mothers is at an all-time high in the U.S — over 26.

The change is largely due to a big drop in teen moms. But more first births to older women also are tugging the number up, said T.J. Mathews of the Centers for Disease Control and Prevention.

He’s the lead author of a report released Thursday that put the average age at 26 years, 4 months for women who had their first child in 2014.

The government began tracking the age of new mothers around 1970 when the average was 21. It’s been mostly climbing ever since, and spiked in about the last five years.