Apple and Spotify are generating $7 billion a year in streaming music revenue

That’s what you get when you combine the 40 million paying subscribers Spotify reported earlier this fall and the 20 million Apple announced Tuesday, and then do some (very) basic math, assuming each subscriber is paying around $10 a month. We’ll have a better grip on those numbers if Spotify goes public next year, and we can see what it really makes per customer. But for now, let’s assume we’re in the ballpark. Peter Kafka, Recode