It does depend a bit on one's personal circumstance, of how many non-refundable tax credits one has. The basic amount these days is in the range of $12,000, so it's quite likely that many people who are in that $20,000 range might be facing income tax on their marginal dollars. For those who are making $15,000 or $16,000, it's much less likely that they're actually paying income tax. When we get into that $20,000 to $30,000 range, that's the place where most people start to pay income tax.
On April 30th, 2018. See this statement in context.