Hard to say. All I can tell you is that my boy grew like a weed till about six months and then his growth slowed way down. Between 6 months and now (18 months), he's probably only gained about 10 pounds. He's stayed about 79 pounds since January.
They sure do change in those first few months! I've got his 13-week puppy pictures rotating as my screen saver right now and it's amazing to think that just over a year ago, he was SO much different.
"Folks will know how large your soul is by the way you treat a dog." -Charles F. Duran