While growth was ultimately positive, the increase was insignificant. The total number of smartwatches shipped in 2016 numbered 21.1 million, an increase of 1.4% over the previous year. The Apple Watch is dominating the market by a significant margin.
http://www.notebookcheck.net/Smartwatch-year-on-year-sales-barely-increased-in-2016.195514.0.html