Mobile captured a record 51 percent of the $72.5 billion marketers spent on U.S. internet advertising in 2016. In its latest Internet Advertising Revenue Report, the Interactive Advertising Bureau (IAB) notes that U.S. internet advertising spending was up 22 percent from 2015, while mobile advertising’s $36.6 billion in 2016 increased 77 percent over the previous year.

“Mobile fueled the internet economy in 2016, with advertisers showing their confidence in digital to achieve their marketing goals,” says Randall Rothenberg, president and CEO of IAB. “This increasing commitment is a reflection of brands’ ongoing marketing shift from ‘mobile-first’ to ‘mobile-only’ in order to keep pace with today’s on-the-go consumers.”

The past year was also a strong year for digital video in IAB’s study. Its $9.1 billion was a 53-percent increase over 2015’s $5.9 billion, and there was a strong showing on mobile devices, with video revenues in the channel more than doubling—145 percent—to nearly $4.2 billion. It was also a healthy year for social media advertising, which climbed 50 percent to $16.3 billion, and search, up 19 percent to $35 billion.

“In a mobile world, it is no surprise that mobile ad revenues now take more than half of the digital market share,” says David Doty, executive vice president and CMO at IAB. “Digital video’s powerful ability to attract engaged audiences is naturally attracting greater investments.”

IAB found that retail advertisers accounted for 21.3 percent in 2016, with financial services at 13.3 percent and automotive at 12.5 percent rounding out the top three. Media advertisers were the fastest growing, their 5.2 percent share represented a 13 percent increase over 2015.