The digital ad market in the U.S. is expected to grow 15.9% in 2017, exceeding $83 billion, according to estimates by market research firm eMarketer. Growth will be driven primarily by increased advertising spend on Facebook and Google.

Display ad revenues for Facebook are expected to grow by 32.1% this year, which exceeds eMarketer’s previous predictions. Meanwhile, Google’s overall ad revenue will reach 14.8% growth in 2017. Furthermore, Google’s share of search ad revenue in particular will increase 16.1%, making up 77.8% of the total U.S. search market in 2017.

As it pertains to overall digital ad revenue, the eMarketer report also predicts that Facebook will claim market share from Google, Twitter and Yahoo, and will make up 39.1% of the digital ad sector in the U.S. in 2017. That’s up from 35.4% in 2016, and is expected to grow to 43.7% by 2019.

In mobile advertising, Google and Facebook will continue to grow their market share. Google will account for 32.4% of revenue in the U.S. this year – a tally expected to reach 33.8% by 2019. Meanwhile, Facebook will represent 24.6% of the mobile market this year, with its share increasing to 26.5% in 2019. Subsidiary platform Instagram is expected to make up 20% of Facebook’s mobile revenue this year, up from 15% last year.

eMarketer also predicts that mobile ad revenue market share for Snapchat will increase from 1.3% this year to 2.7% in 2019, while revenues will grow by 157.8% to $770 million in the U.S. in 2017. Meanwhile, mobile ad share for Amazon will rise from 0.6% in 2017 to 1.2% in 2019.

As for Twitter, eMarketer expects ad revenue to fall to $1.3 billion, a 4.7% decrease, while Twitter’s market share will fall to 1.6% in 2017 from 1.9% last year. The platform’s mobile ad share—its top revenue source—will decrease by 4.1% in 2017 to $1.15 billion, while its display ad share will fall from 2.6% last year to 2% this year. Similarly, while Yahoo will see mobile ad revenues rise this year, its market share will decline from 2.6% in 2016 to 2% this year.

In related data, ClickZ Intelligence recently found that almost two-thirds of advertisers plan to increase their investment in advertising on Facebook over the next year. About 40% reported the same for LinkedIn and Instagram, while Twitter, Snapchat and Pinterest come in at 27%, 19% and 16%, respectively. Twitter also has the highest number (11%) of advertisers reporting that they plan to decrease advertising on that platform