Enough so that a human can review every claim. I don't know how many claims they process in a day so I can't give a hard number.
But I suspect the number of copyright claims would go down significantly once they have a bunch of people reviewing them, because the erroneous claims would become unprofitable, assuming they punish entities that make too many erroneous claims.
That could be a tenth of the planet’s working population, and we all know it. It’s not like youtube’s scale is some well kept secret.
If we are thinking about any serious solution and not some philosophical one, just throwing bodies at the issue is a no go (and would be inhumane in my opinion, I don’t want even millions of people spending their life dealing with copyright claims)
Either change the rules about who can emit claim, change how claims are emitted, change the effect of the claims so they’re not so drastic. There’s many realistic directions the issue can be taken.
But I suspect the number of copyright claims would go down significantly once they have a bunch of people reviewing them, because the erroneous claims would become unprofitable, assuming they punish entities that make too many erroneous claims.