It depends on specifics. What is the nature of the employment? What are the hours? Are uniforms included? Supplies? Health insurance? Retirement benefits? Transportation? Certainly it seems excessive but details matter.

The question I think you should be asking isn't about percentages but about transparency, and not just on the part of one employer, but on the part of all. Currently in the US, non-union employers hold nearly all the cards. It makes for such a one-sided employment market that even calling it a 'market' denigrates the meaning of the word. We could start with one simple change, requiring all employers to divulge the wages and specific benefits of each employee, as well as disbursals to all owners.