the unintelligent are always sure, the wise is always doubting...
In fact I am sure that most of you have, at one point or another, heard that most people think they are smarter than average. Of course that isnt possible, due to the very nature of what an average is.
Actually it is possible that more then a half are above average (oder under.)
You are confusing average and median (as many, even very smart people do).
Example: You have 10 people. One owns 10 million dollars. 9 own nothing.
On average everyone is a millionaire. The median (or middle income, you may have heard that) is zero.
In Germany 3 years ago the average income was quite exactly 30K while the median was (equally exactly) 20K.
Today it's a bit higher with less round numbers :D
90% of car drivers think they drive better than average. Looking at that difference it could explain why every tenth driver seems to be a complete idiot that should never have gotten a driver's license.