Here are a few statistics I have gathered. In calendar year 2012, the U.S. Navy relieved 25 commanding officers of various ranks for a variety of misbehavior or poor performance. Over the past eight years, the military services have relieved 226 flag/general officers also for a variety of misbehavior or poor performance. In each of these cases, the leadership lost confidence in the individual being relieved.
On a personal note, I have been reticent to pass judgement or assess these actions. First, I make the assumption that these leaders don’t relieve subordinates without some degree of assurance that “wrong” was committed, and only pass final judgement following a thorough investigation. I remind myself that the devil is always in the details, and I am not privileged (nor have a need) to know these details.