For the first time ever, advertisers in the U.S. will spend more on mobile ads than on desktop-based online advertisements, a new study forecasts. In 2015, mobile will capture 51.9% of digital advertising spend, a change from the past when most dollars were devoted to traditional online ads, the report from eMarketer revealed.

“Brands continue to see increased value in mobile advertising to reach consumers,” says eMarketer analyst Martín Utreras. “Some of the shift is happening organically from digital ad spending dollars, but also we see additional dollars moving from traditional media and new money coming from local advertising and small businesses.”

Over the next four years, mobile’s share of advertising dollars will increase as desktop’s performance slowly declines. This year alone, spend on mobile ads will jump 59%, eMarketer says. Within mobile, display advertising will be the dominant format, accounting for 51.1%   $15.55 billion – of the total mobile pie. Search ads, meanwhile, will bring in $13.62 billion – 44.7% of total mobile ad dollars. SMS messaging ads will tally less than 1% of mobile ad spend, while other formats – mainly classifieds and email – will account for 3.4%.

Consumers are compelling the shift to mobile. People now spend just less than three hours daily on non-voice activities on their mobile devices. Advertisers want to be where those eyes are – a fact that will also see mobile ad spending surpass print advertising in terms of total ad market share in 2015. Mobile will be at 16.6% of the overall ad market, while print’s take will be 15.8%, eMarketer predicts.