The Defense Officer Personnel Management Act of 1980 (DOPMA) states that it should take 15-17 years to make 05 (LtCol/CDR), and that the selection rate should be 70%. Currently the only service that regularly "deep selects" officers is the Air Force. I met a 36 year old 06/Col who was referred to as a "four deep,” meaning he had been deep selected four times. The Marine Corps has not selected an officer from the below zone in over 15 years. That being said I pinned on LtCol at 15.5 years, and I am nothing special.