Hello,

Your percentile is not bad, especially when considering you are also eligible for OBC category. You might get a decent branch even in Tier 2 NITs and some of the good IIITs. Dropping for another year is a very personal decision. You must know yourself if that was your best effort or not. If you feel you can better your performance of this year, then you should definitely take a drop and even try for IITs. 

My verdict is if you feel you can better your performance to the level of Tier 1 NITs or IITs, then you can take a drop otherwise all the colleges including Tier 2 NITs or Even average IIITs are more or less same in terms of opportunities.

Thank You