So: Americans buy more than 3x the number of Prii, Canadians buy 3x more Yarii (likely more than that - if the labels are right, it's only showing CDN hatchback models vs all US Yarii models). Canadians also like Corollas more than the US does.
Too bad there aren't numbers for the Camry & Matrix. I bet we'd see: US favouring the Camry, Canadians favouring the Matrix.
What I've noticed when I visit most Provinces is a stronger sense of responsibility to the Environment. A random Sociological observation shows more people recycling, preserving natural space, and being FE conscious.
Did you grow-up in that environment -- such as at school, around home, work, etc?
Supposedly the relatively new (last decade) Federal Green party is at 13% in a recent national poll. Since December(ish), the environment has repeatedly come up as the #1 national concern for voters.
That said, a federal Green member has never been elected. Next year that'll change, I suspect.
On the car issue, it may not just be environmental responsibility driving the choices: I've also read that (due in part to higher taxes) we have less disposable income than in the US. Add to that the higher (than the US) cost for fuel (taxes again), and you've got some solid financial motivators that affect car buying decisions.