No, it was a campaign to write-in "American" rather than your actual ancestry to "assert your American-ness" that caught fire in Appalachia in 2000 (and will probably be repeated in this Census).
That sort of thing can, which is quite interesting. Around 14% of people in Wales wrote 'Welsh' on their census forms back in 2001.
The difference there being that there is (or a least was, historically speaking) a real Welsh culture, complete with its own language, which is distinct from other cultures in Britain, whereas "American culture" is merely an amalgamation of various foreign cultures that has adapted into something unique.
