GPCI, how unique ?

Hello!



I'm making a GPCI based ban system, and i am aware of the fact that the GPCI aint so "original", that it's more likely going to be the same on multiple clients.



But how unique is it? How many different values are there? Anyone who knows that?



As far as i know, the best method is to compare with parts of the IP which is banned aswell to get a better probability rate.



Thanks for any answers :P