• More than 14 million young adults nationwide — or 21.9% of people ages 23 to 37 — live with their mothers, up from 12.7% in 2000.

• More millennials live with their moms in areas where rents are less affordable.

A growing share of young adults should be extra thankful for their moms this Mother's Day: They're still living with her. Nationwide, 14.3 million people between the ages of 23 and 37 live with the woman of honor, not too far off from the number of children under age five who do the same (18.3 million). And the share of young adults living with mom has grown considerably: It’s now more than a fifth (21.9%) of them, up from 12.7% in 2000.

The share of young adults unable or unwilling to flee the nest was fairly constant for the first half of the 2000s, with approximately 13% living with mom. But when the housing market went bust and the economy began to unravel into a recession, the share of young adults-at this point, the millennial generation-living in their childhood homes understandably increased as they graduated into a weak economy where jobs were difficult to obtain.

Despite a fairly robust economic recovery, young adults are increasingly living with mom instead of breaking out on their own. For many, this could be a pragmatic choice in the face of rising housing costs and deteriorating affordability over the past 15 years. Some may simply be unable to afford local housing costs; others maybe could afford those costs, but choose to live with mom instead to more easily save for a down payment, security deposit or other big expense. It's also worth noting that a small, but meaningful, share of young adults have mom (and possibly dad) living at their home, perhaps to take care of their parents as they age or to have help raising children of their own-childcare, after all, is expensive. But only 1.4% of young adults are in this situation, virtually unchanged from 1.2% in 2000.

There are a few exceptions to the national trend. In 12 of the largest 35 metropolitan markets, the most recent cohort of adults between the ages of 23 and 37 have started to break away from this trend. A smaller percentage of young adults are living with mom in Atlanta, Boston and Seattle than were a year earlier. The decline is by no means dramatic-often times just a percentage-point or two-but hints that we might start to see this trend level off.

Striking, given the robust economy

It's striking that such a large share of millennials live with their mom because the economy has rebounded since the Great Recession, and unemployment rates in general are near historic lows.