This should help get you started :)
I arrived at this thru a percentage of 45% (45.3) to be exact.
Please let me know if I can assist you further. Please dont Rate my answer until you are happy :)
I hate to be obtuse; however, I am still not sure how you arrived at your answer. Can you give me the exact formula you used.
I can do better than that :). Here is my Workbook with a table showing how i got my answers.
Seeing it in the spreadsheet helps greatly. I thought I was going to lose my mind figuring this one out. Now that I see it, I feel a little stupid for not getting it sooner.