I have wondered the same thing. I'm not sure O&D numbers exist for that train. While I have certainly ridden the train between Toronto and New York several times, I'm not sure why any sane person would do it. You can drive it in 2/3 of the time and fly in just over an hour. It's hard to determine how many people actually cross the border and how far they go on either side. I'm sure Amtrak has numbers for the US-only ridership and VIA has theirs for the local service they treat it as.