Facebook brought in $5.6 billion in ad sales during the fourth quarter of 2015, a 57 percent year-over-year increase, the social network revealed in its earnings report today. Eighty percent of Facebook's quarterly ad revenue, or $4.5 billion, came from mobile, up from 69 percent in 2014.
Facebook's ad revenue for all of 2015 totaled $17.1 billion compared with $11.5 billion the previous year.
The fourth-quarter boost partly came from brands' holiday budgets, which are typically larger than other times of the year. During the earnings call, Facebook's chief operating officer, Sheryl Sandberg, said that coupled with a shift toward mobile and Instagram ads helped bolster 2015's numbers. Sandberg also said 98 percent of Facebook's biggest advertisers ran Instagram ads during the fourth quarter.
Outside of advertising, an average of 1.04 billion users accessed Facebook every day in December, 934 million of who logged in through its mobile app.
Sandberg also said that people now watch 100 million hours of video every day on Facebook.
In terms of monthly active users, Facebook had 1.59 billion in December; 1.44 billion of them came from mobile.
"Our community continued to grow, and our business is thriving," CEO Mark Zuckerberg said in a statement. "We continue to invest in better serving our community, building our business and connecting the world."