By Derek Haines on Just Publishing Advice:
What is the price balance between selling ebooks and Kindle Unlimited reads?
Since Kindle Unlimited (KU) was introduced in 2014, the number of Kindle ebooks available on KU is now around 1.4 million.
Of these available titles, the vast majority are by self-published authors who have enrolled in Amazon KDP Select, and a smaller proportion is from Amazon’s own publishing imprints.
Very few, if any titles are from the major publishers.