13 combined corps , 76 brigades , about 7 battalion each ,let say 10 company per battalion on average.
A company has 6 officers , that comes out 420 officers per brigades , that without the staff positions at brigade in reality, so lets say 500 for simplicity.
So for the ground forces alone , for field formations alone I would expect 6500 officers , not all of them are infantry , and not all of them is been replaced each year.
A reasonable assumption would be half of the officers come from infantry schools , and 30% of them discharge each year , so 1100 if quite reasonable.
Honestly the math I did here is on the low end , it wouldn't surprise me that there would be 2 times as much officer positions