As I quoted in a post on the previous page
Did you read the whole 1270 pages of the document to find that quote? ;)
The data on ancestry were derived from answers to long-form questionnaire Item 10, which was asked of a sample of the population.
So the map is based on roughly 16.7% of the available data? Now that's what I call "creative statistics"...
The ancestry question is still strange though. The document states that
"The intent of the ancestry question was not to measure the degree of attachment the respondent had to a particular ethnicity. For example, a response of ''Irish'' might reflect total involvement in an Irish community or only a memory of ancestors several generations removed from the individual."Which seems to support my earlier notion that people didn't really know or care how they answered that question. Hmmmm ... I vaguely remember that one of my ancestors came from Prussia ... so let's state that my ancestry is "German" just to be done with this nonsense ...