Counting multiple values from a lookup

Hi all,I am currently trying to puzzle out how to count all of the distinct instances of yes and no from a lookup I have done.The lookup is =IIF(Lookup(Fields!Supplier_Code.Value,Fields!Supplier_Code.Value,Fields!First_Name.Value,"DataSet2")="","No","Yes")However I can't for the life of me find the right syntax to resolve this.Hopefully one of you will be able to helpThanks in advance.