(Telecompaper) Spotify has passed the milestone of 10 million paying customers. The streaming music service counts in total 40 million active users, including its free, ad-supported service. Its reach has grown in the past year from 36 to 56 countries. The company said it has paid more than USD 1 billion in royalties to artists since its launch in 2008. It also reported a high retention rate, with over 70 percent of the first subscribers to its premium service in 2010 still signed up for the service.