Streaming music giant Spotify has confirmed that it now has more than 100 million active monthly users, people that listen at least once a month. That’s up from just 75 million a little over a year ago and equates to adding around 1.8 million users each month although things aren’t as clear as they initially seem.

If you recall, Spotify crossed the 30 million subscriber mark (also known as paying members) back in March. Engadget reached out to Spotify for updated numbers but was told they have nothing new to share at this time. If Spotify’s active monthly user numbers continue to rise but paying memberships stall, it would suggest the company is having a hard time convincing free listeners to pony up money for premium benefits.

Spotify still generates revenue from free listeners via advertisements but it would obviously love to move those users to the paid category. Spotify Premium removes advertisements and offers improved audio quality and the option to download tracks for offline listening.

The Swedish company launched in 2008 but didn’t expand to the US until a few years later in July 2011. Spotify has exhibited impressive growth over the past several years, especially in the wake of rival services like Rhapsody (soon to be rebranded as Napster), Apple Music and Tidal. Whether or not its growth translates to a long-term, sustainable business model, however, remains to be seen.