Also, understand that someone who obtains a nom is not necessarily qualified to receive an appointment. For example, last year one of my candidates had a LOA and a nom. Guaranteed appointment, right? Wrong. Was not medically qualified.
People who receive noms can also not be academically qualified by USNA or may fail their CFA.
In the past, USNA would publish the number of candidates who were triple Q'ed with noms and the number who received offers of appointment. If memory serves -- the numbers typically were about 1800 of the former and, as 64 says, maybe 1400 of the latter. However, I don't believe USNA published those numbers for 2013 or 2014 -- if they have, I haven't seen them.