Pima is correct. Usually, the two numbers involved are:
1. No more than 4400 total cadets at the academy
2. No more than 1000 graduates per year.
This doesn't always work out. For instance, the class of 2012 had approximately 1280 walk into BCT. On graduation, there were about 1070. And during that time, the academy fluctuated above 4400.
So, the answer to "How Many" appointments will be offered this coming spring, for the class of 2019 is........ "Whatever the academy wants". I wouldn't go as high as 1350-1400, although it is possible. Chance are, it will be between 1175-1250. Why did I pick those numbers? Because I've seen more than enough classes go through, and I know that the air force and academy still have financial and personnel goals they want to reach. So that is my guess. It could be 1050 and it could me 1350.