The more I read about legitimate, anecdotal experiences in the gym, the more I become convinced that these cliche, hard and fast rules really don't apply to everyone.
I don't know that there is an answer. There are probably too many variables, because everyone's body is different. On top of that, you have people of a unique physiology who have different rest, sleep, dietary and activity level preferences, along with the possibility of use (or lack thereof) of various supplements (we'll go with legal just for the sake of argument here). All of those can affect gains in a calendar year.