In Australia, it is illegal to not vote. If you are over 18, you must register as a voter. If you do not, you are subject to a fine. If you are a registered voter, you must vote. If you do not, you are fined. So, I imagine, they essentially have a 100% turnout for each election. I think you can also choose to vote for ‘none of the above’, although their whole system is slightly different: it’s an ordered preference system.
Could you imagine a similar law in Canada? How would that change our political landscape, as it’s often the lament of the left that the people who are least likely to vote are the people most likely to be left-leaning.