actually, I can say for some reason I've been stuck at 64 for several months now, as long as I can remember. I have no idea why it's been so tough to break on through to 65, but I'm sure it'll happen sooner or later! :)
As for some people growing faster than others, I think part of that is the "luck of who's discovered you", and that "luck" seems to be boosted by those who participate in some of the STEEMIT discord communities and such as well.