Not a majority, no, but as I understand it there are more people identifying themselves as Germans than any other group. So, for instance, if there are 33% people of German ancestry in a county, there is no other single group with a higher %-age than 33 in that district, right?
I think most Swedes identify themselves as "Americans". There are some almost pure Swedish towns in Minnesota, but they might still view themselves as Americans.
And Callaway also knows how to spell anglicized, as opposed to the "PhD" and the Moomintroll.