Online banking has passed a milestone in the U.S. — more than half of adults now use it, according to a report released Wednesday by Pew Research Center. And among internet users (who make up about 85% of the U.S. population), 61% bank online.

The report also took the pulse of mobile banking usage in this country and found that 32% of U.S. adults and 35% of those who have cell phones use it. The Pew project interviewed 2,252 adults this spring.

On both digital banking fronts, adoption has grown considerably in the past three years. In 2010, Pew found that 46% of U.S. adults (58% of internet users) were banking online. In 2011, only 18% of cell phone owners were using mobile banking.

E-banking is more common in younger and wealthier population segments. Among those aged 18 to 29, 67% use online banking and 54% use mobile banking. Similarly, in the 30-to-49-year-old segment, 65% use online banking and 40% bank on their mobile device. Among seniors (over 65), online banking is still used by almost half (47%), but mobile banking is used by a scant 14%.

The wealthiest Americans, with more than $75,000 per year in household income, are heavy users of online banking — three quarters say they do — and mobile banking (44%). However, those with a bit less income ($50,000 to $74,999) were slightly more inclined to bank on a mobile device — 45% say they do.

These numbers are not surprising, but confirm the need for banks to ensure their services adapt well to a range of computing devices including smartphones and tablets.