New data from the Pew Research Internet Project released on Friday has revealed that Instagram was the fastest growing major social network among adults last year.

According to the study, the segment of U.S. adults using the photo-sharing app grew nine percent over 2013, meaning 26 percent of the U.S. adult population is now on Instagram.

That marks the biggest jump of any major social network studied, surpassing growth by Pinterest (seven percent), LinkedIn (six percent) and Twitter (five percent).

Facebook, on the other hand, didn’t expand its user base among U.S. adults at all last year, staying steady at 71 percent, according to the study.

However, it should be notted that the data isn’t perfect. It excludes U.S. teenagers who are heavy users of many of these services, and, of course, all international users. It also excludes data on other popular social networks from the past year, like Snapchat.

Instagram announced 300 million active users in December, a 50 percent increase from just nine months prior.