What percentage of graduate students studying science in the US
graduated from US public high schools? What percentage of graduate
students studying philosophy in the US graduated US from public high
schools? What percentage of people in the US graduated from US public
high schools?

Dear Sarah, 

Your question is about to expire without having been answered, and you
might be disappointed.

A possible reason for that could be your pricing, which might be a bit
low for the type of research requested. 

In addition, you've asked three questions, each a difficult one, on
one posting - dividing them into three postings would have increased
the chances of them getting answered.

Here is a link to guidelines about pricing your question, in the pricing guide:
https://answers.google.com/answers/pricing.html - I hope this would
help you price your next questions on Google Answers.