I do not know those figures because they concern other disciplines, not the Social Sciences and Humanities Research Council. I am not sure if those figures are comparable in my field.
That being said, I think there is a perception that we would have better luck if we submitted an application in English, the claim being that if we did, we would be better understood, have access to a broader pool of evaluators and increase our chances of getting a grant.
These are questions we ask ourselves when we send in applications to the federal government. We wonder whether we have a better chance of getting a grant if we submit an application in French or in English. We also wonder about the language abilities of external evaluators.