Part of the reason why U.S. lawmakers consider TikTok a threat to national security, and therefore moved to ban it, is due to the app’s enormous popularity.

In December, 20% of U.S. adults reported using TikTok several times per day, according to figures from data intelligence firm Morning Consult. That’s up from just 4% who said the same in January 2020.

Meanwhile, around half the country logged into the app at least sometimes just before it shut down.