Yeap. Couple of facts for a few that not know.
Senior Master Sergeant (E8) in the AF: Only 2% of the entire enlisted force across all 4 services can be promoted to this grade. This is mandated by congress.
Chief Master Sergeant (E9) in the AF: Only 1% of the entire enlisted force across all 4 services can be promoted to this grade. This is mandated by congress.