According to IPFI there are actually 68 million:For all this talk about billions of potential customers and years of head-starts... I think we're ignoring one simple thing:
There are only 45 million paying customers of on-demand streaming music on Earth.
http://ifpi.org/news/IFPI-GLOBAL-MUSIC-REPORT-2016
Currently it's the biggest growth driver for the music industry. From the link above:Perhaps paid music streaming is not, and will never be, a big industry overall.
"
- Digital sales contribute 45 per cent of industry revenues; overtake physical's 39 per cent share
- Streaming revenues up 45.2 per cent, helping to drive 3.2 per cent global growth
Helped by the spread of smartphones, increased availability of high-quality subscription services and connected fans migrating onto licensed music services, streaming has grown to represent 19 per cent of global industry revenues, up from 14 per cent in 2014. Streaming now accounts for 43 per cent of digital revenues and is close to overtaking downloads (45 per cent) to become the industry's primary digital revenue stream."