I went to two stores near me, Macy's and Nordstrom. The lady in Macy's measured me as a 36AA and said that "that size makes it very hard to fit you." I bit back the impulse to launch a volley of 4-letter words in her direction, and instead politely told her that I was sorry, but these were the only breasts I have, but that I would work on trying to make them a size that was more convenient for her.
I went across the way to Nordstom, where the lady found the same two breasts to be a 34B, and was easily able to find a number of (really expensive) bras that fit me perfectly. It cost me US$60, but I ended up buying one because they fit so fantastically.
The moral of the story is to shop around.