You almost have it exactly reversed. Industry standards state funds to the focus of the charity should be 75-80% of donations, with the 20-25% for overhead. There really cannot be a major charity with the ratio you cite, it would be a scandal and out of business, maybe even under indictment.
Well, I was thinking of the Red Cross, in particular, but there were others.
I just googled it, and according to this site, 90.1% of donations are spent on program expenses, while only 5.9% are spent on administration:
http://www.charitynavigator.org/index.cfm?bay=search.summary&orgid=3277
Of course, most of that is included in “Program Expenses,” presumably getting workers to where they are needed and the like.
How much of Santorum’s charity’s travel expenses, meal expenses, etc., are devoted to similar ends—getting people where they are needed. I don’t know, and the article doesn’t say.