(Telecompaper) Music streaming service Spotify has announced that it reached the milestone of 15 million subscribers and 60 million active users at the end of 2014. The company had previously revealed in November that it had a subscriber base of 12.5 million, up from 10 million in May. Spotify launched a US-only promotion at the start of December offering three months of its ad-free Premium service for USD 0.99 instead of the standard rate of USD 9.99 a month. It also began rolling out its Spotify Family service at the end of October, enabling users to invite up to four family members and share one billing account.