> Yet more Americans know their zodiac sign than their blood type,

I mean, most people get a reminder of their birthday once per year, but blood type? You have to test for that and most people just don't see that sort of thing come up. The average person neither gets blood transfusions obviously (and it's not like medical professionals take what you state about your blood type for granted, so remembering doesn't help) nor have a good reason to donate.

If anything, it's good that Americans aren't doing Japanese blood-type personality beliefs. I hope they never do.