My proposal is described in 16 pages. You're asking a question that would be on page 17.
Clearly, there are a lot of specifics that would need to be put in place in order to press the go button on this. In my proposal, what I suggest is that the contributions start above $30,000. In other words, low-income workers are largely, from an income replacement point of view, covered by OAS, GIS, CPP. So this is a middle-income issue that would start at $30,000 and take it up to the maximum wage where you get full deduction, which I think is currently about $150,000. Over that range, a 10% deduction would lead to a target income replacement, including pillars one and two, of about 60% of final earnings.
That's what the target benefit is designed to be in my proposal. If you do the math on what kind of contribution rate you need in order to hit that target, it works out to about 10% of pay, from $30,000 up to the maximum.
Another question is, where does that 10% come from? In my proposal it would be split 5%-5% between the employer and the employee. Again, you get to the question of mandatory versus optional. In my proposal, both parties have an option to opt out.