The CAT percentage is just one of the factors old IIMs see to select you. There is a multitude of other factors like X, XII score, your bachelor's GPA, your work experience and the quality of it. The weights given to each of these is different for different IIMs and hence, the range of CAT percentile varies. 

Having said that you must try for a minimum of 99 for A and C. B gives a lot of importance to other factors I mentioned and there have been cases where students with 97-99 percentiles have also made to the list. Same goes for Lucknow and Indore. 
P.S.: This is for general candidates. For candidates with quotas, the cut off is quite less.

The CAT percentage is just one of the factors old IIMs see to select you. There is a multitude of other factors like X, XII score, your bachelor's GPA, your work experience and the quality of it. The weights given to each of these is different for different IIMs and hence, the range of CAT percentile varies. 

Having said that you must try for a minimum of 99 for A and C. B gives a lot of importance to other factors I mentioned and there have been cases where students with 97-99 percentiles have also made to the list. Same goes for Lucknow and Indore. 
P.S.: This is for general candidates. For candidates with quotas, the cut off is quite less.