I agree with OP. I don't have figures but I suspect that more and more students are competing and that there aren't more awards being given out. For OGS it'll depend on your school, faculty, and how competitive the year is, at my school it seems like it was extremely competitive.
I got rejected for both master's CGS NSERC and OGS/QEII, but it's very strange for me to see because my marks are extremely high, I almost won the award for highest average (my school ranks students each semester, and I'd usually be top 3), and I have a lot of extra honours on my degree like dean's honour list, etc. I've done a lot of unrelated work (restauraunt etc) for money during school semesters instead of doing research at school, so that's my weakness, but I still did industrial NSERC's during summers and I even hit the 3-time limit on industrial work NSERC's. I also don't have any journals or presentations, so that's another big weakness.
I know I have a lot of room for improvement, but it's shocking because at the master's level at least I know they put a big emphasis on the grades instead of research in contrast to doctoral awards, where's it's majorly your research work that determines if you get it. But in the end I really do think it's getting more and more competitive each year.