All this poll shows is that a large percentage of people don't listen to the questions they are asked. That's a basic problem of streets surveys. You basically ambush people with a set of questions when they are occupied with a thousand other things.
Stuff like "What is George W. Bush's first name?" or "How long does it take the Earth to travel around the sun?" always gets weird answers.
I am not shocked so much by the survey's results but by the fact that my own best friend did not know. It was not a matter of how the question was asked. We discussed it for a couple of minutes and she definitely had no idea what a year was nor did she understand that the Earth rotated once each day.