Probably less than a thousand people with a thousand private keys own 85% of the bitcoins. Remember, if its in an exchange, you don't own it. You are trusting them.
Also, that would imply 85% is being used as investments and only 15% is Available to spend.
Though they definitely don't have sort of "true ownership" due to them not having control over the keys, they technically still own the bitcoin that they deposited in the exchange.
And no, it doesn't imply crap. You can't come to that conclusion just by that statistic alone.