Hello.

It is not possible to tell you what your percentile would be if you scored 128 out of 200. As you know, percentile depends upon the number of students who have appeared for that exact exam in the same year. As the number of students appearing for an exam keep fluctuating each year it is not possible to tell you your percentile.

Also please do mention the name of the entrance that you have appeared for so that you can atleast find the cut off mark or percentage or make assumptions bases on that.