We have the list. It's not by state, but by metropolitan area in the U.S. It's Canada-U.S. We have to stop talking about the largest trade partner in terms of U.S. states, because I think that's actually fairly meaningless. The largest trade partner means 1% of a state's GDP, but when you get down to the metropolitan area, that's where it means something.
On May 18th, 2017. See this statement in context.