140,000 is the rough number of civilian contractors in Iraq, engaged in all sorts of activities, from catering through infrastructure to communications, etc.

40,000 is roughly the number who are there as gun-toting backup to the Army, who participate in fighting and the training of Iraqi security forces.

But I can't find the article I got that impression from, so maybe I just constructed that idea in the back of my mind. I'll google around a bit and see if anything pops up.