Engineering is very, very competitive as well.
You can get up to 800 applicants per year for co-op, of which only about 20 I would roughly say (disclaimer: I am not too sure about this need a clarification) will make it to interviews possibly. However what I do know is that across the whole engineering faculty, there will only be roughly 8 or less co-op scholars coming in every year.
See with engineering, the training for engineers costs companies a lot of money. Hence they are less inclined to train many students who are in uni.
Even once you graduate with engineering, the hardest step is finding your first job and getting that experience you need to break into engineering. However once you make it in, things get a whole lot easier because it will cost companies less to train you over some specific skills and so they will be more inclined to take you with valuable experience than spend money on untrained graduates.
In comparison to commerce/financial/info systems/whatever else there is, I know for BIS and CIS they had about 60 people interviewed altogether and about 15 to 20 got a co-op offer. My mate and ON clarified this earlier in the year (soz if I have some of the numbers wrong because this isn't something I'm expecting to remember wholly after 10 months of not thinking about it).