hi eliza.you are quite right to surmise that a "pass rate" would be hard to determine.fact is the pass rate is 100% non sinful.only Jesus attained that measure.he gave his life for us,the sinless on behalf of the sinful that all who repent and believe are accounted righteous and accepted by God.as Jesus said -john 14 v 6
"i am the way,the truth,and the life,no man comes to the Father but by me"
perhaps you know JOHN 3 V 16 ,if not its well worth looking at this wonderful invitation.   blessings pete.