According to the latest Association of American Publishers (AAP) net sales revenue report, adult hardcover sales plunged 20.9 percent in November 2011, dipping from $219.9 million to $174 million compared to the same period the year before. At the same time, total trade book sales dipped 3.5 percent.

Above, we have embedded a year-to-date chart above for 2011, but we still need to wait for the December numbers to get a complete picture of book sales in 2011.

Here’s more from the release, drawn from publishers’ insights: “While the November over November e-books number [65.9 percent increase] is still high, it dropped below the triple-digit percentages we’ve seen in the past year.  The year-to-date percentage growth remains pretty consistent with what we’ve been seeing all year.”

Editor’s note: This post has been updated to for clarity.