Most of the more straightforward answers to this question end up with you making the majority of that million from your entrepreneurial skills rather than software development skills. (For example, "Found a software development consultancy and grow it to 8~12 employees.") In terms of straight up W-2ing without taking entrepreneurial levels of risk, I think you're looking at either finance or (restricting 25% to ~10%)…
I doubt top 10% at Big 4 are getting $1mn/yr in wages.
You're welcome to your own estimate as to the percentage -- I suppose it's quite sensitive as to whether you're thinking "percentage of engineering staff at AppAmaGooBookSoft" (which is weighted towards < 5 years of professional experience) or "my percentage odds of reaching that level mid-career given 5 years of competent execution at one of AppAmaGooBookSoft."