Spotify, the most popular music streaming service in the world, announced today that it has reached 10 million paid subscribers worldwide. Most importantly, the company, which is lead by CEO Daniel Ek, has shown considerable growth in the top music market in the world, the U.S.

Since it launched in the U.S. in July 2011, Spotify’s paid service has over 3 million subscribers here, according to sources for Billboard. The overall 10 million number for subscribers worldwide is also up significantly from the last time Spotify made numbers public in March 2013. At that time, the company said it had 6 million paid subscribers.

Spotify currently has 40 million total users, so one in four are now paying the $10 monthly fee.

In an interview with Bloomberg Businessweek, Ek said that the company’s main focus is getting people to stream music, so if they keep that in mind, more people will upgrade their accounts to paid subscriptions.

“We know if you do that, you’re going to be like, ‘Hey, 10 bucks is nothing. It’s like two beers,’” Ek said. “In Sweden, it’s actually less than one beer.”

Still, the main challenge for Spotify remains staying alive as the streaming music industry gets more competitive. While Beats’ Beats Music service seems to confirm that Spotify’s model works, it could also jump ahead of Spotify if that $3.2 billion purchase by Apple goes through.

Spotify has continued to grow, though, especially after the mobile app became available for free. Ek told Billboard that 80 percent of new users are now signing in on mobile devices.

“We’ve really become a mobile-first company,” Ek told Billboard.

Billboard notes that there has recently been talk of Spotify making its initial public offering, possibly later in the year.