Commenter Peter's insight from a previous post in which he pointed out that my estimate that 85% of Hispanics were choosing "white" as their race struck him as too high led me to look at it more closely. Given that I was estimating for affluent small cities, it seems reasonable to expect a greater proportion of Hispanics to have European features than do in the country as a whole.
My thought process wasn't that sophisticated, though. I was under the impression that 85-90% of Hispanics do choose "white" as their race in the Census. The Census QuickFacts page is a resource a use regularly for reference, and it suggests as much.
Nationally, the Census reports for '06 that whites (including Hispanics) represented 80.1% of the total population, while non-Hispanic whites comprised 66.4%. The difference is 13.7%, presumably accounted for entirely by Hispanics who chose "white" as their race. I presume this because the white, black, American Indian or Alaskan Native, Asian, Native Hawaiian or other Pacific Islander, and two or more races categories sum to 100% of the national total--there is no "other" catchall category presented. Hispanics (14.8% of the total population) are falling into one of these categories, the vast majority (92.6%) being classified as white.
At the city level, however, QuickFacts does not include a non-Hispanic white classification. The other categories presented fall short of 100% when summed, with the difference presumably being made up by those who went with the "other" category (which is also not presented).
This NYT article reports that 97% of those who self-describe as members of some other race are Hispanic. The other category is, then, essentially a Hispanic category that represents 42% of the Hispanic total. The article also reports that 48% of Hispanics define themselves racially as being white (only 2% choose black, with the remainder choosing two or more races). Together, that represents 90% of Hispanics, awfully close to the percentage of Hispanics QuickFacts reports to be white at the national and state levels.
So it looks like unless an "other" category is explicitly presented or implicitly implied due to the stated categories not summing to 100% of the population, it should be assumed that Hispanics who elected "some other race" are being grouped in with those who've chosen white as their race.
It'd be less confusing if "Hispanic" could be an exclusive racial category, maybe "gold(en)" to go along with black and white. That wouldn't represent the diversity of the Latino community in the US, of course, so I'll perish the thought.