[mixu]

I use revenue per employee as a rough guide to the type of company in question (is it human-based or tech/marketing-based? is it a startup or an established business?). It's simple to calculate, and revenue is usually less sensitive information than net income per employee (so easier to get for non-public companies). My feeling is that for the average (non-public, not particularly successful but OK, non-automated) company the average salary is about 1/3 of that (more or less). Actual net income per employee of course depends on the degree of automation and success.

Example tables:

http://www.jbryanscott.com/2009/02/07/nasdaq-100-revenue-per...

http://37signals.com/svn/posts/2283-ranking-tech-companies-b...