if the player decides to be mute the dealer will say how much it is.
As DCJ noted, I do not believe this is the current trend as a matter of procedure... if a player decides to be mute about how much he has behind, it's not up to the Dealer to then chime in. The chips are not yet part of a wager so the Dealer has no obligation to count it - the player who is thinking of calling needs to know how to count chips behind a player by sight - that is part of the game. As long as they are arranged "where it can be easily seen and estimated accurately", then this should not be a problem.
The other thing is that if the Dealer does chooses to intervene and voluntarily gives a count, and then gets the count very wrong, this is going to create a whole new series of problems that you'll have to deal with later... How are you going to explain that the players should not have relied on the dealer's count in the first place? Why open this can of worms?