Usually more emphasis will be placed on your later years, but they do look at it all in most cases. For programs like Law, Medicine, etc. I've seen specific mention of schemes for dropping your worst classes, etc. (note that those are more properly "Professional Programs" rather than "Grad Programs"), but I haven't come across specific mention of stuff like that for most Master's programs.
Remember that it often takes just as long to do a search or two on Google to try and find the answer to your question as it takes to type it in a post here, let alone the time waiting for a reply.
If your question is "What mark does it take to get into University X", or "What are the requirements to get into University X", it's on their website and/or
electronicinfo.ca (for Ontario schools). Particularly for Ontario schools, those ranges are a pretty good picture of what kind of mark will get you into the program, and if you're more than a couple percent higher it's practically guaranteed unless it requires a supplementary form.
