I think the source of the error is likely an interplay of domain privacy and the fact that one of the largest registrar's on the globe, Tucows, is Canadian based. I saw in Dofo blog a couple of years ago some stats that seemed to show Canadians were dominating a bunch of extensions that I knew, or felt pretty sure, was not true. When I drilled down, it was registrant country data on whois being used. That in many cases now reflects the privacy service. For example, if you have xyz registered at Dynadot, with privacy on, it shows registrant region as California, USA, even though you properly have the real registrant data set to Canada. Under privacy, it is essentially impossible to get a true picture on data like this.
-Bob