Of those interviewed, approx. 20% are accepted with 30-35% being placed on the wait-list. Rejected applicants are notified as soon as possible.
Applicants are notified in mid-April if they have been placed on the alternate list. Greatest movement from the list occurs from May 15-June 1.
[Whether it will be of benefit or not, I don't know, but it should do no harm to write a simple, short letter to indicate your interest in remaining under consideration. Again, whether it will do any good or not, if you have significant new information to add, do so briefly in the same letter. Do not be a beggar.]