A Bankrate study released Monday finds that 67% of millennials don’t have credit cards. It’s the only adult demographic group where credit card ownership is that low—55% and 62% of 30-to-49 year olds and 50-64-year olds, respectively, have them, while ownership among American 65 and older is even higher.

The survey also highlights several other distinct socioeconomic trends when it comes to credit cards. For instance, nearly three-quarters of poor American how make less than $30,000 per year don’t have them while 81% of those who make more than $75,000 do. There are similar disparities between high school diploma holders and college graduates.

“Millennials are clearly falling short in terms of credit card usage compared to their elders,” said Mike Cetera, Bankrate.com’s personal loans and credit analyst, in a statement. “A credit card shouldn’t be seen as taboo. Used correctly, a credit card can not only provide the added benefit of points and rewards, but also help establish a healthy credit score which will be valuable for such things as a lease or mortgage in the future.”

Previous Bankrate surveys have shown similar results, explaining that several factors including the availability of debit cards and concerns about possible debt play into millennials’ credit card avoidance.

Millennials stand apart from older generations in several facets of personal finance. For instance, not only are they less likely to own credit cards—the ones who do tend to have smaller outstanding balances (although they aren’t always as good at paying off those balances). A Fidelity report from earlier this year also found that millennials are outpacing other age groups in retirement savings.

Meanwhile, overall American credit card debt could hit $1 trillion this year, according to Federal Reserve data.