VBA Function to Declare Yes = 100 and No = 0

I have a spreadsheet that has drop downs all throughout the spreadsheet. It is for the purpose of an audit of our communities. Let say that A1 = Yes, A2 = Yes, A3 = No

What I want is to SUM(A1:A3) but instead of summing Yes and No, which is can't do, it will see all the Yes's as 100 and all the No's as Zero. Is this possible?

Thanks for your help