While I'm on the subject of discussing admit demographics, I'll also follow up on the post I made last year regarding the military Class of 2011 at HBS.
HBS has made a very genuine effort to provide active duty military personnel the opportunity to attend and succeed at HBS. The new HBS Class Co-President is former military, and military personnel continue to be regarded in very high regard on campus. It's definitely our responsibility not to take that for granted and to continue to earn that respect by contributing to the Harvard community and upholding its long tradition of excellence.
In addition to increasing the GI Bill Yellow Ribbon package to $10k/year (matched by the VA for a total of $20k), the Class of 2012 also shows a 19% increase in former active duty US military personnel.
At 4-5% of the total class, HBS has taken a leading position among the top MBA programs as a school that places a premium on military experience.
I'll note that there were also three foreign military personnel from non-compulsory service nations to be admitted as well (2x Britain, 1x Greece). There are also at least three women matriculating from the military, compared to none in Class of 2011 and two in the Class of 2010.
So it looks like soldiers and sailors really increased their game this year, and unfortunately I won't be around HBS next year to report on the Class of 2013, so this will have to be the best information out there for a while.
Note: As usual, I'll clarify that my data is not from admissions and is therefore not necessarily perfect and is definitely not official. It is however very close.