This has worked in teh Past
First Year - Two O's needed for Second Year
Seconds Year - Three O's Needed For Third Year
Third Years - Four O's Needed For Fourth Year
Fourth Years - Five O's for Fifth Year
Fifth Years - Five O's needed for Sixth Year
Sixth Years - Six O's needed for Seventh Year
Seventh Years - Must Pass O.W.L.S & N.E.W.T.S & Be Approved to Graduate