Even those of us who believe in God can't decide that, because our different religions teach us different acceptable moral practices.
Is there any way to condense different acceptable moral codes into a consolidated, single code? (Sort of like Jesus saying, "Love God....heart, soul, mind, strength...and your neighbor as yourself.)
In the case of Jesus' code, to say that NO ONE has ever achieved "total morality" is to say, depressingly, that no one has ever really, totally loved. That would be an empty world.