SIX percent of respondents never heard of Joe Biden, you know, the guy who is in his 7th year as Vice President of the United States? That's sixty (60) Americans in this poll who have never heard of their Vice President.
That's not the least bit surprising. A Newsweek poll in 2011 showed that 29% of people polled couldn't name the vice president:
http://www.newsweek.com/how-ignorant-are-americans-66053Other polls over the years have shown similar numbers. It's not uncommon for a solid minority of people to not know who the VP is. There are plenty of people out there who don't follow the news at all.