There are a number of different surveys that look to measure global use of drugs. There was a survey released by, I believe, UNICEF a number of years ago that put Canada as the top ranked country in terms of youth use. There are other international instruments that look to measure youth use. While the particular methods and the results vary, the results across the board show that Canadian youth do use cannabis at rates that typically exceed their peers in like countries.
On September 11th, 2017. See this statement in context.