It is around 40 posts. So it can be more or less. I think you will reach Jr. Member soon.
It is at 45 posts but not for less posts.
Forcing someone to post in the forums is not actual way to develop it.
I mean they weren't forced to create an account in the forum. Posting shouldn't be a problem if they intend to become part of the community. Ranking up is just a benefit of contributing and being actively engaged in the discussions.
We all create for making money in the forums, however some may wish to post regular and some can't like I went offline for a year and returned to this forums again. Posting here really helps to everyone including forum traffic rank, but some won't like to be a regular poster.
I read somewhere in this thread that if someone don't post then their points would get lost. I read something like this in this thread.