It is not about the number of posts,it is about the number of searches that the keywords that you are targeting have.
The more posts that you do,the more searches you can have.
It will be like,for each post you will get 5-20 visitors a day. (this is figurative numbers,depend on market and rank positions.)
If you have 100 keywords in your market that has searches,then the more keywords you cover,the more searches you will have.