I don't understand these numbers; I'm sorry.
There is no way that the immigrant population, if we want to call it that, can increase numbers in any substantial way to the English school system. It is possible that francophones do attend English schools in Quebec; in fact, in some parts of the province there are considerable numbers of them because of a parent or grandparent who went to school in English. It means that English school systems rely, as I think I said, on people from outside the narrow community in order to fill their schools.
I still don't understand how that fits into the statistics, though. We'd have to have a much more detailed breakdown in order to understand that.