How much muscle mass in a year?

Tubby2Toned

How much muscle mass can a person gain in a year?

And of course, I mean this in a fairly broad sense. Understanding that men are different than women, testosterone levels vary, age, initial body types, and genetics all come into play, I'd like to know if anyone has any real data on this subject.

The data I've found seems to be all over the place.

I was told once by a body builder that the most a man could gain in a year was 8 lbs, without the juice.
I recently discovered some research that showed that a study group was able to gain 8lbs in 12 weeks.

Any real solid info on this anywhere? Let's say our guinea pig is an average man or woman who is generally fit, and decides to get into heavy weight lifting for a year. At the end of the year how much muscle poundage would they gain?