Take this as you will:
For class of '17 AND in my company, 5 of my classmates dropped out during plebe summer and one dropped out during the AC year.
For the Class of '18 and in my company, no one dropped out Plebe Summer, but 6 have dropped during the AC year and I've seen similar patterns throughout the Brigade.
Some might say this is due to recent changes of how Plebe Summer is allowed to be ran by detailers. Whether this is the case or not, I do not know and I am not here to debate that. What I am saying is that 4 years at the academy alone will test if you should make it as an officer rather than Plebe Summer alone. To speculate what attrition rates will be for future classes, in my opinion, is unreasonable and unpredictable, because no matter how selective the selection board will be for future classes, even if on paper it's the best class yet, you'll never know how a person will react to all the variables of stress, camaraderie, honor, responsibilities, etc. until they actually go through 4 years here.
Like I said, take this as you will. I'm only a 3/C here and I can say there are people in every class, including my own, who I look at wondering "How did they get into this place?" and people who make myself wonder "How did I get into this place?" Though more times than not, the academy will sort out those who belong from those who don't.