The Tale of manga: The UCLA International Institute reprints a speech by Prof. Lynne Miyake in which she dissects the manga adaptations of the 11th-century Japanese novel, The Tale of Genji. In her analysis, Miyake provides a nice overview of manga in Japan:

"In 1995, the peak of manga publication and production, 1.9 billion -- or 15 manga for every man, woman, and child in Japan -- were sold. This figure did not include the dôjinshi (or amateur manga publications), or mawashi-yomi when one manga was passed and read by several people. Since that time the statistics have fallen to 1.5 billion in 2000, the latest figures I have, but this still accounted for one third of unit sales and nearly a quarter of the gross sales of all publications for that year.

"Perhaps in recent years, manga reading on trains has been eclipsed by people engaging in text messaging or surfing the net on their cell phones, but Japanese manga have certainly left their mark. Manga is ubiquitous in Japan: it is used for a variety of tasks, ranging from training new bank customers in the whys and wherefores of banking, on the one hand, to instructing employees on how to estimate the cost of sewer construction, on the other."