PEW just released new data on adult book readers. The data are focused specifically on books and relates reading frequency to several demographic variables (income, education, age). Twenty-six percent of adults admit to reading no part of a book in the past year. Younger, better educated, and more affluent adults are more likely readers. The % of adults who have read an ebook is surprisingly small (28%) with better educated adults more likely to use this format.
The study ignores many related issues and makes little attempt to explain reasons for reading or not reading. It is unclear whether nonreaders consume information in other ways to make up for less reading.
I found it interesting that reading content related to work drops off quickly, but reading to understand current events does not.