Facebook has 1.5bn daily active users; 93% of ad revenue is mobile

"Daily active users (DAUs) – DAUs were 1.52 billion on average for December 2018, an increase of 9% year-over-year.
Monthly active users (MAUs) – MAUs were 2.32 billion as of December 31, 2018, an increase of 9% year-over-year.
Mobile advertising revenue – Mobile advertising revenue represented approximately 93% of advertising revenue for the fourth quarter of 2018, up from approximately 89% of advertising revenue in the fourth quarter of 2017.
Capital expenditures – Capital expenditures were $4.37 billion and $13.92 billion for the fourth quarter and full year 2018, respectively.
Cash and cash equivalents and marketable securities – Cash and cash equivalents and marketable securities were $41.11 billion at the end of the fourth quarter of 2018.
Headcount – Headcount was 35,587 as of December 31, 2018, an increase of 42% year-over-year."
Source:  Facebook Q4 & full year 2018 results, 30th January 2019