Someone I know has recently completed their Jasmer grid (Number of months hidden), and they asked me if I knew how the top 18 cachers (in the UK) are sorted, as they're all on 191 months.
I can't see any obvious way that they've been sorted. It's not by date completed, it's not alphabetical, and it's not by number of caches. So I said I didn't know, but I'd ask the question. It might be that it's just random, but I don't know.