There are 21 ranks:

1: Leader
2: Commander
3: Co-Commander
4: General
5: Lieutenant General
6: Major General
7: Brigadier General
8: Colonel
9: Lieutenant Colonel
10: Major
11: Captain
12: First Lieutenant
13: Second Lieutenant
14: Chief Master Sergeant
15: Serior Master Sergeant
16: Master Sergeant
17: Technical Sergeant
18: Staff Sergeant
19: Senior Airman
20: Airman 1st Class
21: Airman