Facebook lost around 2.8 million U.S. users under 25 last year. 2018 won’t be much better.

Facebook is losing young users even quicker than expected, according to new estimates by eMarketer.

The digital measurement firm predicted last year that Facebook would see a 3.4 percent drop in 12- to 17-year-old users in the U.S. in 2017, the first time it had predicted a drop in usage for any age group on Facebook.

The reality: The number of U.S. Facebook users in the 12- to 17-year-old demographic declined by 9.9 percent in 2017, eMarketer found, or about 1.4 million total users. That’s almost three times the decline expected. There were roughly 12.1 million U.S. Facebook users in the 12- to 17-year-old demographic by the end of the year.

There are likely multiple reasons for the decline. Facebook has been losing its “cool” factor for years, and young people have more options than ever for staying in touch with friends and family. Facebook also serves as a digital record keeper — but many young people don’t seem to care about saving their life online, at least not publicly. That explains why Snapchat and Instagram, which offer features for sharing photos and videos that disappear, are growing in popularity among this demographic.

Overall, eMarketer found Facebook lost about 2.8 million U.S. users under 25 last year.

And Facebook’s 2018 doesn’t look much better.

The research firm released Facebook usage estimates for 2018 on Monday, and expects that Facebook will lose about 2.1 million users in the U.S. under the age of 25 this year.

EMarketer predicts that Facebook will see a decline in usage among all three age groups for people under 25:

• A 9.3 percent drop for Facebook users under 11 years old. (Reminder: Facebook’s terms of service require that users must be 13 years old in order to create an account, though it’s easy to get around that.)
• A 5.6 percent decline in users between 12 and 17 years old.
• A 5.8 percent decline in users between 18 and 24 years old. This is the first time eMarketer has ever predicted a year-over-year decline in usage for this age group, though it has happened before. In 2016, Facebook’s user base for 18- to 24-year-olds fell by 1.5 percent.

Take the numbers with a grain of salt — eMarketer is an outside research firm so it doesn’t have the full picture that, say, Facebook has.

But the fact that eMarketer is predicting declines across the board is a bad sign for Facebook regardless. Young people offer a good barometer for what is popular, but more importantly for Facebook, losing out on the next generation of internet users in the U.S. is troubling for the company’s long-term dominance.

The good news for Facebook is that, despite the expected decline in younger users, eMarketer believes Facebook’s overall U.S. audience will continue to grow for the next few years. More importantly, perhaps, eMarketer expects Facebook-owned Instagram to grow significantly. The research firm believes Instagram’s U.S. user base will grow by 13 percent this year, to almost 105 million people.

That’s even better than Snapchat’s expected growth — eMarketer believes it will grow its U.S. audience by 9 percent in 2018. That would give Snapchat about 86.5 million users by the end of the year.