There are two variables in those numbers. The one unaccounted for is number of hunters. I can tell you where I hunt, used to be a very big and productive area but after about 1980 (claims of the big blizzard, and farming changes) the number of hunters has dropped by magnitudes. Used to be thousands of hunters in the fields, now there might be a few dozen.
And bird numbers are pretty good, IMO. I'll put up 50 on a bad day and as many as 300 into the air on a good day. And the states are not in the survey!