There are few factors that influence a cut off. The number of candidates who appeared for the exam, the difficulty level of the exam and the number of seats available.  If the exam was tough, the cut off will be less and if the exam eas easy, the cut off will be higher. So every year there will be a difference in the no. of people who appear for the exam.and also the difficultybin the exam. No 2 years data can be the same. Thats the reason there will be difference in the Cut offs.