^ the sad reality is that for Canadian stats you have to go the a US site...........APTA.
www.apta.com has quarterly ridership reports on all US and several major Canadian systems almost always including Montreal. They break down the ridership for each system by mode of transport ie bus, Metro, LRT, commuter rail etc so you should be able to get your stats from there.
They actually get their stats from CUTA but CUTA won't release them for Canadians so you have to go to APTA.