It depends on the various aspect of your academic career mainly
1) 10th
2) 12th
3) Bachelor's degree

For IIMA

If you have 80+ percentage in 10th , 12th and bachelors , then around 99.5+ percentile is a decent CAT score to get a call . But if you are lagging in any one of the three aspect , then you certainly need to score around 99.8+ score to get a call .

For IIMB

In addition to a decent CAT score like 99.5+ , you need to make sure you have 80+ percentage in your 10th , 12th and bachelors . If you are lagging in any of these three then there is hardly any chance for you to get a call untill  you had a good work experience to compensate it .

For IIMC

They don't give a shit to your bachelor's degree . Just score 99.5+ and have 80+ in 10th and 12th thats it . and If you ar a girl you have an added advantage .

For rest IIM , the criteria is similar but you still need 99+ score to get a call from old IIM