Any way to know where is the biggest dot in my document?

Hi guys,

I have a client asking me if I can pinpoint the biggest dot in my document. I don't have any other way than selecting the dots 1 by 1... problem is that I have 500 000 of them (halftone pattern). Now I don't want to go crazy before finishing this project so I am thinking there might be another way to do it.

Any of you have ever had this problem?

Thanks,

S