I'm not basing this on any reliable data. Just based on my own personal searching and being on constant look out for Autobiography rangies, so take it with a grain of salt.
To me, it appears that 2010-2011 were the heaviest years in AB production. I've just seen more 10's and 11's autobiographies for sale. I've seen some 09's and below, but those are much harder to come by than 10-11's.
Then, in the next level of rarity I think are 2012 autobiographies which are harder to find. All are topped by the rarest which seems to be the 2012 autobiography ultimate. Probably followed closely by the 2011 Autobiography Black (I've only seen two "Black" versions in 2011 cars...a fellow member posted pictures in the thread shared above).
Plus, add to that the fact that apparently somewhere AB's were "normal" orders and some were custom-ordered and received a tag in the engine bay. I'd love to know more details, but as datafoo mentioned, LRJ wasn't very forthcoming with info. Nevertheless, given the total production of L322's...any autobiography is already pretty rare.