I think some of the reasons the gap hasn't closed is that there wasn't an effective mechanism in place under CHRA, because even in complaint-based, unions are better able to use it. Certainly in Ontario, even using the proactive law, unionization still remains one of the most effective ways to close the pay gap, just by itself, because generally when women are unionized their wages rise and the pay gap closes, and it doesn't require them to file a complaint.
On October 28th, 2010. See this statement in context.