Depending on how you classify Jews, (personally I classify them as non-white) would depend on how you classify white Americans to a certain extent. Roughly 10% of white Americans will have at least some Jewish blood. Very few white Americans, even young ones, have any African American blood, except those from the Southeast who average around 1%, which is basically nothing. If you are a nordicist who doesn't consider Greeks, Italians and Spaniards to be white than I suppose only around 60% of white Americans are actually pure white but it's still a majority. You can still find a ton of very pasty white Americans with freckles, red hair or blonde hair who look the same as an Irish or Brit with just a bit more sun exposure. I'd say on average your average American has the same complexion as a Frenchman, which while not as light as a Brit, is still pretty light.