I only know details for the University of Waterloo engineering program, which has a lot of students from China. In 2017, there were 4000 international applicants and 200 spots available for internationals. The chances for domestic applicants was roughly twice that of an international applicant.
Roughly 80% of Waterloo’s international students are from China. It’s 60% at U of T, 35% at UBC and 23% at McGill. Some universities could stand to increase their marketing in the US and other countries.