Amazon Music tells Billboard it has “tens of millions” of paid customers, with Amazon Music Unlimited subscriptions having more than doubled in the past six months, according to data provided by the company. Amazon, the third-largest streaming service behind Spotify and Apple Music, did not clarify the exact number of paid customers it has.

But in an interview with Billboard, Amazon Music vp Steve Boom says that growth is down to two main factors: the large — and expanding — number of people who subscribe to Amazon Prime, and the growth and popularity of smart- and voice-activated speakers, with Amazon’s Echo leading the way.

Billboard

The popularity of Echo and Amazon Prime I can see that being a driving force. The same way Apple has the iPhone and was able to get into subscription music late and get a large market.