A lot are consultants, at least at HP and IBM. (Microsoft and DEC are much more engineering-heavy; I've heard that Microsoft has the structure of 1 engineer, 1 PM, and 1 tester per team.) Remember that out of Google's headcount, only about 20,000 are engineers. When I was on Search, Bing had more engineers working on it than Google Search.
How many of those were really engineers, rather than managers, marketing people, consultants, support?