Mobile accounted for 78% of Facebook’s advertising revenue, up two percentage points from Q2 and 12 percentage points from a year ago.

Marketers spent $4.299 billion on Facebook ads during the third quarter and about 78% of that spending—roughly $3.353 billion—was spent targeting the social network’s mobile users.

There’s a good reason for retailers and other advertisers spending so much on Facebook’s mobile ads: Facebook has nearly 1.39 billion mobile monthly active users and 894 million mobile daily users. Moreover, Facebook-owned WhatsApp has 900 million monthly active users and Messenger has more than 700 million monthly active users. For the sake of comparison, Twitter has 320 million total monthly users (and 256 mobile monthly active users). And Facebook and Instagram, which has 400 million monthly active users, account for one out of every five minutes U.S. consumers spend on mobile devices.

As Facebook’s user base grows—it says its monthly active use base grew 14.4% over last year—it is also finding ways to drive more advertising revenue from each user. The average revenue per user worldwide grew nearly 28% during the quarter, compared to the third quarter of 2014. And in the United States and Canada, average advertising revenue per user grew nearly 49%.

“We’re really pleased with marketer adoption of our ad products around the world,” said Sheryl Sandberg, Facebook’s chief operating officer, during a conference call with analysts. “Our results show that we continue to make progress on our three priorities: Capitalizing on the shift to mobile, growing the number of marketers using our ad products and making our ads more relevant and effective.”

For the quarter ended Sept. 30, Facebook reported:

  • $4.501 billion in total revenue during the quarter, a 40.5% increase from $3.203 billion in the same quarter of 2014.
  • $4.299 billion in advertising revenue, a 45.4% increase compared with $2.957 billion.
  • Mobile advertising revenue represented approximately 78% of all ad revenue during the quarter, up from 66% a year ago. That would indicate mobile ad revenue was approximately $3.353 billion during the quarter, a 72.0% increase compared with roughly $1.950 billion a year earlier.
  • $2.83 in average advertising revenue per worldwide user, up 27.5% from $2.22 a year ago. Facebook calculates average revenue per user as its total revenue during a given period, divided by the average number of monthly active users at the beginning and the end of the period; that is why the average revenue per user doesn’t equal revenue divided by its number of active users.
  • $9.86 in average advertising revenue per user in the U.S. and Canada, up 48.5% from about $6.64 a year ago.
  • Net income was $896 million, up 11.2% from $806 million.
  • 1.007 billion daily active users, an increase of 16.6% compared with 864 million last year.
  • 1.545 billion monthly active users, up 14.4% from 1.350 billion.
  • 894 million mobile daily active users of on average in September, an increase of 27.2% from 703 million.
  • 1.385 billion mobile monthly active users, a 23.2% jump from 1.124 billion. 
  • Of those monthly active users, 727 million only accessed Facebook through mobile apps or mobile versions of its web site. That’s up 59.4% from 456 million.

For the first half of the year, Facebook also reported:

  • $12.087 billion in total revenue, up 40.3% compared with $8.615 billion to the same period in 2014.
  • Net income was $2.127 billion, a 5.0% dip from $2.239 billion.