Amazon.com Books Bestsellers: The most popular items in Audiobooks. Updated hourly

How many audiobooks are commercially available? What is the percentage of the total book counting? What about the difference between sales of single titles and sales tied to subscriptions? I haven’t done any research on the subject, so this might sound naif — all the answers might be somewhere already (please point me in the right direction if you have a clue <grin>). The fact is that today I tried to look for something interesting to buy, and the result has been quite disappointing. None (or almost none) of the titles in my Amazon wish lists has an audio version. The most popular items list (see above) is full of self-help books, with a good bunch on diet, cutting fat in a week etc., a sizeable group on marriage, divorce etc., then a few fiction best-sellers… Am I just not aware of the all thing or what?