The “How many idiots?” question (gauging public intelligence)

If you enter a public bus in any average American city/town, and there are 10 other passengers already aboard, then how many of these 10 passengers do you think are actually idiots?

I’ve always thought 3, but now I think 5. My wife says 1. My friend truly believes that 7 of 10 are idiots.

PS: I consider myself slightly above average, but smarter than my wife and friend lol