I, obviously, cannot say exactly what your professor had in mind; but these sorts of statistics usually measure something like percentage of people with access to the internet(either at home, at work, or in cybercafes) often with some sort of weighting (person with 100mb fiber to home counts for more than guy who uses a 36.6 at the internet cafe twice a month).
http://www.internetworldstats.com/top10.htm is an example of a basic "(users/total population)*100" type analysis. It seems to indicate that we are ahead of Canada, though I cannot vouch for the quality of its data. General wisdom, as I hear it, is that internet penetration rates are highest in parts of northern Europe(especially the smallish Scandinavian ones) and parts of the east (e.g. Japan).
Even beyond the usual troubles with collecting accurate data, though, is the question of what exactly you mean by "use". Some might consider broad but shallow access to the internet to be high use(e.g. more or less everyone can at least check their email a few times a week) while others might say that high use means "everyone who matters has at least 10 megabits down, 2.5 up, always on, three or more computers, at least one internet capable PDA or cellphone, pays all their bills online; but who cares if the 80 percent of people outside of the cities never touch the net at all?"
In Manitoba we also have a very expansive DSL network, and it's only pennies more per month than the Dialup that is offered, so pretty much anyone that can have DSL uses it.
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