Google and Facebook are expected to stay at the top of the digital advertising market, reports eMarketer. The research firm expects U.S. digital advertising spending to reach $83 billion in 2017, a 15.9-percent increase over 2016 and that Google and Facebook will account for more than half of 2017’s revenues.

The search market is expected to generate $28.55 billion in revenues for Google in 2017, up 16.1 percent year-over-year and accounting for 78 percent of the sector’s total revenues.

“Google’s dominance in search, especially mobile search, is largely coming from the growing tendency of consumers to turn to their smartphones to look up everything from the details of a product to directions,” says eMarketer forecasting analyst Monica Peart. “Google and mobile search as a whole will continue to benefit from this behavioral shift.”

Facebook is in a similarly dominant position in display advertising. eMarketer forecasts a 32.1-percent jump in its display business this year to $16.33 billion, 39.1 percent of the U.S. display market. Contributing to Facebook’s revenue growth is Instagram, which Facebook bought in 2012, 18 months after its launch, for $1 billion. In 2017, it will account for 20 percent of Facebook’s mobile revenues, up from 15 percent in 2016.

“Facebook’s users are increasingly captivated by videos on the platform—not just on Facebook, but on Instagram as well. Video, both live and recorded, is a key driver of growing user engagement and advertiser enthusiasm,” adds Peart.

While still in Google and Facebook’s shadow, eMarketer expects strong growth from Snapchat. In 2017, the platform’s U.S. ad revenue is forecast to grow 157.8 percent to $770 million. This year it will account for 1.3 percent of the U.S. mobile ad market, growing to 2.7 percent in 2019.