So FerretBoy, what you're saying is that the program is only reporting numbers of individual close pairs, rather than clustered groups

Yeah, but with such a small number of pairs (80 or so) you have to think there's not much clustering, which was what I felt the program was revealing. However, the modifications I have in mind will point out exactly what you want, though I hadn't thought of putting a graph in the program. I might do it, depending on how bored I get at work.