I get 68 marks and 84.20 percentile last year but this year I get 95 marks and 84.74 percentile. then what is reason of decrease percentile on high marks

Hello,

See, The exam is held on multiple days and sessions. The difficulty level of the exam differs in every session. To ensure, correctness while evaluating the performance of all the candidates.

The percentile is based on marks secured and converted in the range of 100 to 0 for each session, normalization is based on comparing candidates scores appeared in the different shifts., highest raw score and percentile score and lowest raw score and percentile score.

Last year the session in which you appear for the exam might be tough so the percentile was according to that. And this time the exam level  might be easy so your percentile is less even after scoring more score.