I was just handed a couple of very new looking 2019 toonies yesterday in my change. I was excited as it though they were the 2020 toonies which I have not yet seen in circulation. They are both 2019 with 16 serrations.
I've been doing some toonie roll hunting over the past two weeks. Out of maybe 50-60 2019s, only one has 16 serrations. I now have 3 of them (including the two I received in my change). So I can say I'm not seeing the same percentage as others.