Just to add a little more detail:
> Music publishers can take anywhere from 10% (for an admin deal) to 50% (for a co-publishing deal). Bigger percentages involve advances (recoupable payments against future royalties), but also much longer terms (5-10+ years).
Note this is for the publishing royalties only (not performance rights)
And on @alex1'- post:
> The label will own the song recordings, not the artist.
This would depend on the contract, though it's true that in most cases today the label would own the recording.
In some cases the artists choose to sub-license the recording to the record company, in which case he/she/they retain rights to the recording.
Finally, as is well known now artists often get an advance from the record company on signing a contract. This advance however is deductible from any earnings the artist would receive. Sometimes the advance is used to pay for the recording or equipment or even to finance a tour (the tours are usually not financed by the labels, aside from the 360 arrangements someone else mentioned.)
No-one has mentioned the artist manager fees - I'm not sure of what the figures for that are, but I think they range from 10% up to 50% (of the advance) in some very rare cases.
In short, in most cases making a living as a musician/recording artist is hard to impossible. Many semi-successful indie bands don't earn much more than a minimum wage job, with perhaps similar long-term prospects. If you make it big, you're rich but anything else is not a great existence. Oh, and the record companies often struggle too (both majors and indie these days.)