I think you raise an excellent point about the migration of people. We also have to remember that the Canadian border is extremely long. Asylum seekers move through natural corridors; there are about four natural corridors across Canada. What is different about this year compared to other years, and this is the anomaly, is a large number of people using one specific corridor though Lacolle, Quebec. Otherwise, the migration patterns, as well as the nationalities are very much aligned with the historical trends.
On September 28th, 2017. See this statement in context.