Apple’s music streaming service has 17 million paying subscribers, adding 2 million customers since June, Apple CEO Tim Cook said on Wednesday.

Cook, speaking at Apple’s press event in San Francisco, credited numerous exclusives from top musicians for helping attract more customers. Cook said Apple Music had carried 70 exclusive launch debuts from artists including Taylor Swift, Drake, and Frank Ocean.

Apple introduced its streaming music service just over a year ago. Tied to Apple’s popular devices, the service has quickly grown into the second-largest subscription music streaming service, trailing only Spotify, which has more than 30 million subscribers.

Apple is expected to reveal updated iPhones and a revamped version of its smartwatch later at Wednesday’s event.