According to research, smartphone owners spend 80% of their time in their three most-used apps. And as the app market matures, it turns out those three apps are usually owned by Facebook, at least according to download statistics.
During May, Facebook, Instagram, Messenger, and Whatsapp combined to account for more downloads than every other app combined. (Apple isn’t included because its apps aren’t downloaded, but preinstalled on iPhones instead.)
Thanks to @westr for pointing us to this article.