Quite a bit. For your subscription YouTube will take 45%. The other 55% are split among other creators by watch time of the subscriber. For what it’s worth, the creators I watch love that system and benefit from it quite a bit. It’s more consistent and safer than ad revenue.

I'm not sure of the exact numbers, but I remember recently listening to a podcast or something where they mentioned that premium users' views are worth a little bit more than ad watchers on average. I'm assuming that's because there's no third party advertiser that needs a cut.