[Brozilean]

I remember seeing something about a very low percentage of viewers being YouTube premium, but accounting for something like 40+% of revenue.

[Mirioron]

That depends on how much ads pay, how many users watch ads/use adblock, how much they watch etc. Videos that get few ads or low-priced ads might indeed have the membership be a large portion of the revenue. Generally it's more in the 10-20% range though.