Different IIM's have different Criteria. For Example: IIM A gives 10% weightage to graduation marks for the Initial Calling while IIm B gives 15% Weightage to the Graduation marks for the Initial Calling.

For the final Selection both these IIM gives 8% weightage to the Graduation marks.

So Considering you scenario, you need 99.4 percentile and above to get a call from the top IIM's.