I've been crunching some numbers on books by authors who died in 1950, and whose works thus became public domain in Canada on January 1, 2001. This is a preliminary sample of what will eventually be a much larger sample of titles. Of 1042 books by such authors, by 2001, only 3.4% were still "in print". ("In print", for the purpose of this experiment, was defined as a work that had been re-issued in the past year, or in any year thereafter, assuming, solely for the sake of argument, that a work that was re-issued in 2005 was still in economic use in every year before. My other model will, eventually, allow for works to come in and go out of print.) Of that 3.4%, 1.0% were "normative" for lack of a better word; republications, translations, and adaptations that are, on their face, authorized by the copyright owner as one of the bundle of rights. The other 2.4% were "special", including audio books and e-texts prepared for the blind and visually impaired, microform research editions, and public-domain-under-US-rules Project Gutenberg editions. At the time of the deaths of the authors of these works, in 1950, only about 12% of their collected works were still in print. That's in year 1 of posthumous copyright. It only goes down from there.