For August (which was a pretty average month, stats wise) the figures look like this:
Total Pages: 9,609,513
Total Visits: 723,426
Total GigaBytes: 289
Broken down into daily stats ( Average) and (Max)
Pages per Day: (309,984) (361,368)
Visits per Day: (23,336) (27,403)
GigaBytes per Day: (9.3) (11)
W.r.t that last one - imagine if somebody connected to your computer and day-in day-out downloaded over 9 Gig of data from it !
PPRuNe uses some serious bandwidth, and hence why we have to have the banner ad's to pay for it !