I'm a bit puzzled about the ancestries figures at the end of your post:
'Ancestries: United States (21.4%), English (11.3%), Irish (11.0%), German (6.9%), Italian (2.4%), Scotch-Irish (2.2%).'
Surely the 21.4% listed as United States ancestry must also be part of the other ancestries (ie English, Irish etc) or they must be native Americans? As far as I know, there are no people in the US whose ancestry is purely from the US and not Native American. Am I missing something here?
Also, be careful if you approach a Scotsman and describe him or his lineage as 'Scotch' - he will probably chin you! People from Scotland are Scots, Scotch is a drink!
A lot of people answer "American ancestry" if they have several ethnic ancestries or are unsure what their ethnic ancestry is. Native Americans *do not* answer "American ancestry."