Mr. NavyCanDo posted some interesting counter-information to that earlier . . . I'm at work, and can't do any serious research right this moment. Besides, maybe he's already got the info right at hand?
But I like this approach. If you can make the case Rudy is a big-spender then you'll be able to seriously crimp this campaign.
Someone posted a good graph showing NYC spending under Rudy. I'll see if I can find it, or maybe someone can remember it and post it here. It's quite telling.