Debian usage by Architecture

There are some attempts to show Debian usage by architecture via mirror statistics. Dirk Eddelbuettel writes

Lastly, some concerns were raised about various biases from local mirrors, web caches, multiple installs and what have you. These are fair questions as they all affect how Debian is obtained, installed and updated. But for as long as we don't know why that should be different across architectures, this is not a concern for the question at hand. The concerns reflect uncertaintly about the absolute level of users, but barring additonal information (or hypotheses), they do not affect the distribution of users across architectures which is what this exercise is about in the first place.

I don't see how this can be right. For example, I use an IA64 desktop, so does one other person in my group, and we run two IA64 production servers (this isn't counting the many development boxes). These have all been pulled from apt-proxy on one machine which caches. So my updates at home on my PowerPC would be seen, but only one of the IA64 ones were (the first update to the apt-cache), even though relatively there are more users. So how can mirror statistics really show you anything?

I'd think they types of people running IA64 boxes will be at large institutions and generally updated via local mirrors somehow. They're also likely to have many boxes, rather than just one or two. So I'd seriously doubt the stats for IA64 mean much.