I know it is a tricky question. What do you think, how many Bitcoins are lost forever and are 'out of the network' by lost private keys?
I guess its too big, large number of bitcoin now for sure but I think the only one that can know that is the developer or the bitcoin founders.
I agree, it is big amount of bitcoin lost forever and still counting on that, many bitcoin just burned and lost and just gone.
And for sure no one can say this on how many where lost unless the developers got their details on this but I guess they have this like those frozen account which not is used for almost a year.