I got the number from the NYT article, which said $9.47 to $11.00 in April 2015, then $11.00 to $13.00 in January 2016. That is a one year period, and a 37% increase.

Here is another source that mentions $9.32. https://www.natlawreview.com/article/seattle-minimum-wage-in...

I'm not sure why there are two different numbers, but it was extremely rapid. I'd be happy to leave it using the more conservative figures from your table that they increased it by 36% in two years, as that's still neither modest nor gradual.