Hey saikrishna. 

There is no such increase or idecrease in the cutoff ranks of EAMCET . it is always the number of candidates who are above your rank i.e. people who have scored more than in the exam. This particular thing decides ur cutoff. On an average the cutoff varies from 100 to 50 ranks every year based on the no. of candidates who have appeared for the exam and the no. Of candidates who have scored more than you. 

Hope it helps. Best wishes !