For Feb. 24, Knipfty said 33.3% of all Kindle e-books available were priced at more than $9.99, up steadily from 29.7% of the total sold on Jan. 20. However, the most recent percentage of books at more than $9.99 was slightly lower than the high of $33.8% on Feb. 13.

"The problem is that e-books are not going away," Knipfty wrote Wednesday. "So we just need to focus on the price. As for me right now, I'm reading The Night's Dawn Trilogy. What a bargain. All three books in one download for $8. And they're large books too!"