https://phys.org/news/2018-05-facebook-fast-teens-survey.html

The survey found 51 percent of US teens ages 13 to 17 use Facebook, compared with 85 percent for YouTube, 72 percent for Instagram and 69 percent who are on Snapchat.

The landscape has shifted since a 2014-15 Pew survey which found Facebook leading other social networks with 71 percent of the teen segment.