<Thanks for the post. Sure, let me try it out! However, I didn't understand why you were defining 2 times, 15 min and 1 min. Also, may be I didn't understand it well, with this approach, how do I determine the no. of same timestamps? For ex. from your data, I could have 2 occurrences of, 15/Jun/2003:00:03:44? May be some other timestamp has 5 occurrences and so on?