>Now *this* is the REALLY useful stuff. This tells me a little bit about the >scope of your problem. (It would really be better if you told us how large >your data set or data sets can be, and what sorts of exploration other than >this one you might want to do.) It tells me what sort of 'stats' you want >to >look at, and what you want to do with them. It tells me about the >structure of the data set (the sortedby information is *crucial*), and >something >about the speed of your current code.

Data sets will range from 3 million to over 108 million observations.

Thanks for the suggestions so far.