eMarketer has scaled back its estimates of ad blocking users in the US, reducing the number to 75.1 million. At that level, more than one-quarter (27.5%) of US internet users will use ad blockers this year.

eMarketer’s previous forecast had projected the ad blocking audience would top 86 million in 2017. While the estimate has been reduced, growth is still significant, at 16.2%.

eMarketer defines an ad blocker as an internet user of any age who accesses the web at least once per month via any device (including a mobile device) that has an ad blocker enabled.

As has long been the case, ad blocking is considerably more common among desktop/laptop users than smartphone users. For smartphones, the incidence of ad blocking remains relatively low, at less than 8%, eMarketer estimates. That’s partly because mobile ad blockers are often not as effective—especially within apps—as they are on desktops and laptops.

Not surprisingly, ad blocking continues to be far more prevalent among younger people. This year, 41.1% of millennials will use ad blockers, eMarketer estimates. The level is considerably lower among Gen X internet users, at 26.9%. And among baby boomers, ad blocking is still quite rare at 13.9%.

“Millennials are more likely to have an ad blocker enabled than those in any other demographic group,” said eMarketer forecasting analyst Shelleen Shum. “They are more tech savvy than older adults, more willing to adopt new technology and tend to spend more time on the internet browsing and watching videos.”

Also, publishers’ efforts to restrict content to those with ad blockers enabled seems to be working. And some publishers have made a conscious effort to switch to less intrusive ad formats.