Excel Formula Development for Scorecard

I'm seeking a proficient Excel user to help me with a specific problem. I need to calculate yes/no questions on a numerical scorecard, accounting for null cells.

Here's what I am looking for:

* Average of yes/no responses for cell E10 located on the following 17 worksheets (they are the names of the worksheet):

SBT FB - Ashley Meredith
SBT FB - Bruce Tworeck
SBT FB - Carissa Romero
SBT FB - Chris McBratney
SBT FB - Danae Bell
SBT FB - Danielle Reber
SBT FB - Erica Shirer
SBT FB - Jenna Laporta
SBT FB - Jenna Rohrs
SBT FB - Kayla Drost
SBT FB - Kimberlee Cooper
SBT FB - Lani Harrell
SBT FB - Mackenzie Wilkening
SBT FB - Mercede Hutchinson
SBT FB - Morgan Isham
SBT FB - Nicole Foster
SBT FB - Wayne Freeman

* Note that "yes" is equal to one point while "no" is 0 points.
* Account for null cells in computation because some Testers did not enter a value; therefore, the score needs to be normalized so that their worksheet isn't counted in the average.

The project involves conditional formatting. Your expertise with numerical data in Excel will be particularly relevant for this project.

Ideal Skills:
* Advanced proficiency in Excel
* Expert experience with conditional formatting
* Ability to work with multiple worksheets

I need this completed right now. I am working and have to have it figured out tonight.
* Strong numerical data analysis skills

Thank you.