Apple Music pays out a proportionate share of the subscription income that they receive from their customers to the artists and labels whose content they offer for streaming.
This share of subscription income changes every month and depends on a multitude of factors such as Apple Music's total subscription income from their subscribers, the subscription tier of each subscriber, the total number of streams that take place in Apple Music in a given month, and the total number of an Artist's or Label's content streams in their store in a given month.
Because these factors change each month, there is not a specific amount per stream or download that can be stated.