90% of trade define the index

95% of active stock pickers can't beat index funds...

And ten percent are out of bounds, some loser some gainer.

I be a bit sarcastic, but not by much, the index is mostly what traders say it is when they trade.  95% percent accuracy in constructing a well rounded distribution is great work, I take nothing from the traders, especially since they rarely talked to each other when stabilizing the distribution.