Facebook's user growth is showing signs of stalling out

Facebook stock took a hit of about 19% on Thursday after the social network posted quarterly results below what Wall Street was expecting - and weaker guidance for the next quarter, too.

A big cause of Wall Street's concern: Facebook's user growth, once the stuff of Silicon Valley legend, is showing signs of stalling out.

As this chart from Statista shows, Facebook didn't add any daily active users in North America in the past quarter, and saw a decline in Europe. Year over year, those regions are only up slightly, too. That's bad news for Facebook, considering that those two regions bring in the most average revenue per user.

NOW WATCH: 5 easy ways to protect yourself from hackers