Publishers Weekly walks through Bowker's 2025 ISBN data: US print and ebook assignments crossed four million, with self-publishing accounting for most of the growth while traditional output ticked up more slowly.
The article breaks out categories and recent trend lines so you can see which segments are ballooning. For authors, the takeaway is less "print is dead" and more "supply is enormous" - discoverability pressure is structural when millions of new titles land every year.
(Shortened and summarised to avoid devaluing the source)