Double or Half?

Check out a dusty new chalkboard map of demographic doubling and halving...

How was this made?  With race/ethnicity voluntary response data from the 2000 and 2010 census, the current counts were compared to the previous counts.  Based on this simple comparison, counties having either twice (orange) or half (blue) the previous count were flagged.  These maps consider only the more generalized groups of Asian, Black African American, Hispanic or Latino, American Indian/Alaska Native, and White -not the more nuanced affiliations available for selection within these groups.  It is not based on more focused followup surveys, but rather the good old general decennial census.
Note, this census question is electively chosen by census respondents and individuals' preferences of identity may change, as well as the subtly shifting terms of the survey itself.
So take these maps with the caveat that some places can have already very low populations so doubling or halving can potentially happen quite easily -though in the context of the set of groups this issue actually provides an interesting dimension of comparison.

**Updade**
This map has been updated to correct for a miscalculation of doubled American Indian/Alaska Native counties in a previous version.  The update has revealed different, and more, counties where that population has doubled.