Here's an interesting infographic from Statista that shows exactly what the online digital revenue pie looks like as compared to 2008.
At the end of 2014 there was about 28 million paid streaming music subscribers, which has now topped 41 million so the numbers are quite a bit larger in 2015.
As you can see, downloads still owns 52% of the market, and while that will undoubtedly decrease in 2015, it will still remain a substantial piece of the puzzle for at least a few more years.
What is growing is the number of people that are adopting streaming, either via the free tier or paid subscription, and this looks to really take off now that Apple Music has launched.
What's interesting is that 15% of the market is still made up of ring tones, ring backs and various other technologies that we don't even consider these days, but are still generating significant income.
You will find more statistics at Statista