Over 16m events per month are created on Facebook

"Luckily, many ticketing and social media platforms provide APIs, or feeds for events, where companies can aggregate a large event database. Last year Live Nation promoted 22,000 events, Brown Paper Tickets promoted 200,000, Eventbrite promoted 1.7M, and Meetup promoted 6.6M. Facebook reported that it was creating 16M events each month in 2014 and now has 450M monthly active users of Facebook events. Today, Facebook does not have a strong event discovery solution."

Source;  Blog post by Hugh Malkin, 26th September 2015