Do you mean as base salary or as a bonus? Lots of tech companies report earnings per employee, and the I'm used to hearing that number be in the couple hundred thousand range. Apple is at $400k earnings per employee. That would mean Apple should be paying $20k as yearly salary or as a bonus on average at your 5% rule. Sounds like bonus territory.
Well, ideally, your base salary is pretty low and your bonus is big. This is the model used in finance because the returns are very unpredictable and the standard deviation between the worst and best employees is very large. Bonuses also provide good incentives to employees.
But to answer your question, total comp should be around 5% of the money you book for the firm. So salary + bonus.
I’m sure there are rigorously sourced data of this across all labor positions. There should even be a public repository of those salaries. Mind providing a link?