There's more than one way to average those two counties. Lately they seem to be testing every deer they can in all 4 counties I've looked at. Hunters shot 288 deer in Boone county 2017-2018, so I doubt there are 5000 deer there (anymore), and that's probably a good thing if you are trying to control CWD. I also found a place for WI numbers: https://dnr.wi.gov/wmcwd/Summary/County Max for 2018 was 26.6% of 1486 deer tested, in Iowa county. 2nd place was Sauk at 20.0% of 928 deer. I suck at geography and history in WI so I'd need to study more, and downloading many years worth of data will take time, but that seems grim.