NEW YORK (CNN Money) – Teens are over Facebook. A new study has confirmed what we’ve long expected. Facebook is no longer the most popular social media site among teens ages 13 to 17.

The Pew Research Center revealed Thursday that only 51 percent of U.S. teens use Facebook. That is a 20 percent drop since 2015, the last time the firm surveyed the social media habits of teenagers.

Now, YouTube is the most popular platform among teens — about 85 percent said that they use it. Not surprisingly, teens are also active on Instagram (72 percent) and Snapchat (69 percent). Twitter followed at 32 percent and Tumblr remained the same (14 percent) since the 2015 survey.

When it comes to the platform that they access most frequently throughout the day, Snapchat is king.

Although the study was only conducted among nearly 750 teens in a one month period starting this spring, the new numbers might be worrying for Facebook. The company recently rebounded from its first-ever decline in users in the U.S. and Canada. But overall, its global growth has slowed. The two countries account for 185 million daily users.

Daniel Ives, chief strategy officer and head of technology research at GBH Insights, argued that Facebook’s own Instagram is more important to the parent company than Facebook itself, when it comes to younger users. “Instagram has captured that demographic better than anyone could have expected,” Ives said. The numbers highlight “why Instagram is one of the best tech acquisitions done in the past 15 years.”

Facebook didn’t immediately respond for comment.

The survey also discovered that lower-income teens “are more likely to gravitate toward Facebook than those from higher-income households.” Plus, the Pew study found that smartphone growth among teens has jumped significantly since 2015 — 95 percent of teens said that they own one, compared to 75 percent in 2015. That may explain why 45 percent of teens said that they’re online “almost constantly,” a statistic that has nearly doubled since the 2015 survey.

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