Distribution of international students by type of program:
http://www.international.gc.ca/education/report-rapport/economic-impact-economique/sec_4.aspx?lang=eng
Old stats. but it gives you some idea of the proportion/ distribution.
50-55% of international students are at university level. but this spread across 4 years. so the number of international student at bachelor's level each year is ~48,000 students maximum.
Then you discount for actual graduation rate (!), % apply for PR (not all want PR), language capability (not all students score CLB 10, trust me on this), funding, and other factors.
I don't think the number of "perfect" undergrad student in the pool is more than 10%, or 4,800 students.
Then you gotta add some for Masters and PhD etc. But those are significantly smaller number.
Overall, ~6k - 7k students ==> gone in 3-4 draws.