Yes, if you consider 2016 the 3rd year for PS4 then 2019 is the 2nd year for Switch.
Difference is PS4 only had 1 and a half months in 2013, while Switch had 10 full months in 2017.
This way makes the most sense because it's the closest you can get.
2016 started with PS4's 777th day on the market, 2019 began with Switch's 669th day on the market. A gap of 158 days.
2015 v 2019 would be a gap of 257 days.
Predictions (Made July 2019)
LTD: PS4 - 130m, Switch - 110m, XBO - 52m 2019 : PS4 - 15m, Switch - 18.8m, XBO - 4.8m 2020: Switch - 22m (Peak Year)