Per AAMC data, for the 2017-18 admission cycle-- 1182 Internationals applied to US medical schools and 106 matriculated
https://www.aamc.org/download/321460/data/factstablea3.pdf
https://www.aamc.org/download/321462/data/factstablea4.pdf
Approximately 85% of those 106 internationals were Canadians.