Harvard has published admissions statistics for its class of 2007, and
the answer to your question is that 65% of that entering class
attending public high schools, and 35% attended private schools.
Separately, the data include the fact that 7.1% are listed as
"foreign" students and 2.3% as Canadian. The data does not separately
break out public vs. private high school percentages for the foreign
students. However, because of their small number, the 65%-35% split
shouldn't be significantly skewed by their inclusion in the overall
percentages (if indeed they are included).
Here is a link to the Web page with that information (and more) about
the makeup of the Harvard undergraduate class of 2007:
Harvard College: Admissions: Class of 2007: Statistics
First, I found a secondary source (the Triangle Business Journal) for
the 65% figure by using this Google Search:
harvard "class of" public private schools percent OR percentage
I then performed a more focused search that led me to the linked page
on the Harvard website:
harvard "65 %" "class of 2007"
I am confident that this information is just what you are looking for,
and I am happy to have been able to find it for you promptly. If
anything is unclear, please ask for clarification before rating the