Calculating Percentage based on Dynamic Cells

Hi Everyone,

Need a small help

I need to calculate the percentage based on self populating score. however I want excel/formula to ignore any cells which has "NA" in it so that it calculates the percentage based only on the cells having Numbers.

Now these Cells which contain Numbers might or might not contain numbers based on the "IF" function which decides wether the cell will have numbers or will remain "blank" or have "NA"

To understand better please have a look at the enclosed sample (that would explain my need better)

Thanks In advance