Revenue.

The word you're actually looking for is revenue.

Money that comes from things like royalties and usage agreements are generally not sales and certainly not gross sales.

Of course all this is an irrelevant digression from the fact that "stranger things" doesn't "gross" anything because it is streamed, universally, because a view of it generates no discrete payment or revenue of any kind. The best you can do is look at its share of viewing hours which is not "grossing" anything and estimate how much it plays a role in the overall value proposition for the average netflix subscriber.