You know, this was said so many times that it's not even funny anymore. And the answer usually is the same: It would take too much time and effort to calculate the total percentage translated.
It's a waste of time, and it's not needed in any real way. If you're so curious, you should start looking for a hobbie or something to do while you wait knowing the total % won't make you have a full translation faster, so it's something completely useless and unnecessary.