The majority of those would have made a claim when they arrived in Canada at the border. It could have been at an airport or it could have been at a land border. Depending on the country of origin, it tends to vary quite a bit. As an example, we've had historically a lot of claims from Mexico, and they have been from a combination of people who are already here in Canada, perhaps working, and others who simply showed up at the border, land or air.
On November 29th, 2010. See this statement in context.