First, a disclaimer:
Bookstats is a co-production of AAP and BISG (Book Industry Study Group). It differs from the monthly AAP reports because it incorporates the monthly data (in much greater detail) as well as an extrapolation consisting of an "economic analysis and estimate of the full sizing of the industry. This is based on estimated number of books, titles and size of companies considered commercial (i.e. issued an ISBN general identifier in the past three years)." So there is a fair amount of handwavium and SWAG in the following data.
Basically I am warning you that taking the 2 sets of data and attempting to do large amounts of math will likely end with one or more of us hiding out in Mexico under an assumed name. I plan to discuss the year-end figures I posted a couple months back, but only in a general way.
The AAP estimates that the total US book market in 2012 was up 7% from 2011, and up 14% from 2008. The net number of units sold were also up, though not quite to the same degree.
Sales of downloadable audiobooks were also up significantly over 2011, with the AAP estimating that sales had tripled since 2008. This is largely attributed to an increasing number of mobile devices like smartphones and tablets.
And ebooks, now there is the best news. The AAP believes that the total US ebook market in 2012 (including more than just the AAP members) increased 44% over 2011, with a slightly larger increase over 2008.
Surprising, isn't it? eBook sales increased largely at the expense of mass market paperbacks, with the other paper formats largely holding their own or increasing in sales.
Sorry for not saying more, but I only got them this morning, and I am still thinking about them.
I will note, though, that the AAP believes that ebooks make up 20% of the overall US book market and 21.67% of their members' reported sales. Also, their members account for about 47% of the total book market and 50.6% of the ebook market, meaning that the members have a better share of the ebook market than the overall book market.
I think that the estimate for the ebook market is off by a significant amount. There are many, many self-pub (and indie digital pub) titles that aren't in the AAP member data and don't appear to be included in the extrapolated data. It is my expert opinion that the prevalence of self-pub ebooks are an indication that the AAP members actually have a smaller share of the ebook market than they do of the general book market, and that ebooks should make up more than 20% of the total book market.
I don't have any data to show that the AAP is wrong, but that's my guess. What do you think?