That's a good question.
Historically it was 66 2/3%. I'm not sure where to put the number on the increase, but it should increase.
The other thing you should note is that, if they're making above the maximum insurable earnings, it's even less than that.
What does the future of work involve? It probably involves people in the service sector—relatively highly paid people—facing the kinds of risks that manufacturing workers faced in the 1990s as globalization rolled through the heartland of Ontario and Quebec and decimated work.
If you can work wherever you want, how long is it going to take for your boss to wonder whether maybe anyone can do the work you do? There will be a whole series of contracting out that could happen, putting people higher up on the wage scale at risk. When they fall into unemployment, they will find that this system—which they paid into all their lives—is going to give them 25% or less of their earnings.
You're not preparing people for the future of work if you don't offer better insurance. Increasing the benefit rate and the maximum insurable earnings is a way to do it, though I have to admit I'm not in a position to put a number on that yet. You would want to balance that with the financial constraints the government faces.