30% of the subscription price. That small artists get screwed over is entirely due to labels.

After the service cut has been taken, all money is put in one big pool and them divided by total number of streams and sent to the labels. How the cut between labels and artists is divided is up to individual contracts between artists and labels but usually the majority goes to the labels due to still accounting for cost of producing and shipping physical CDs. Pooling all users money also unfavourably favours big artists and is enforced by the labels as bigger artists makes them more money than smaller ones.