I checked the date, slightly confused. Just to make sure: could you send me the lottery numbers for the last two years?
Anyway, that Facebook about-us page also has an article from summer 2015 about hitting 1 Billion daily active users for the first time. Their growth really isn't that impressive any more (+280Million in two years), mostly because they've run out of people.
Another reply, from @jackmodern, indicates that they may have done that, so now I am less confident that it is the daily actives.