Why are scooters so big in Minneapolis? You guys have that famous scooter shop as well. Aren't you folks pretty far north for so many scooters?! What's your secret?
I couldn't find figures for scooters specifically, but taking "registered motorcycles" as a whole (so including all scoots over 50cc, also our friends on their spyders etc) the top 10 states in "motorcycles per capita" are MT, SD, NH, IA, WY, WI, ND, MN, VT, ID.
So, we have this indication of a strong two wheeled community. Now consider that many of these states have a lot of sparsely populated rural area and a few major cities forming the centers of densely populated areas. Their simple practicality for the urban environment will increase the use of the smaller scoots not included in the "motorcycles per capita", further swelling that number and it will also slightly skew the fraction of "motorcycles" that are actually larger scooters.
Now let's put the cherry on the cake. Scooterville is RIGHT next to a few college campuses, including the UofM, and the U has dedicated moped parking spots all over campus. I'd bet a significant # of the students taking advantage of those will later become motorcyclists or ride bigger scoots.
Plus, the mere fact that Scooterville is there means you can GET them locally, and get them serviced too.