When I say 50/50, I mean value wise. So I actually meant "half of the BTCs have been traded for BCH".
At the moment, the number of extant BTC=BCH.
So, you are not aware that in any BTC/BCH trade, the number of both BTC and BCH stays exactly the same?
So, there is no such a thing as "half of the BTCs are traded for BCH".