Nobody knows.  It's a huge headache for demographers and epidemiologists trying to deal with data, because everybody checks the box using their own definition.  Sometimes multiple boxes, sometimes not.  The original definition is hardly relevant if people filling out forms don't use it.  And I'm a geneticist - don't even get me started on that problem.  Hispanic/latino and/or amerindian ends up being understudied and misrepresented as a result.

I know two cute little girls who are the bilingual, jewish, blond daughters of two well-off doctors.  I don't think this exactly fits the stereotypes some white people hold, but they are in fact hispanic.