It makes sense, because you have a lot of deductions. With that 50% mark of people who don't pay taxes, most of them are students, the elderly, or people who don't have a job, and it all balances out. You have to look at it in a life-cycle pattern. When you're working a lot, you pay more taxes, but when you're studying or you're retired, you pay less taxes. It balances out.
On April 21st, 2016. See this statement in context.