Amazon is releasing new data on its Kindle Lending Library, which the e-commerce site says now has over 75,000 books. The Kindle Owners’ Lending Library is a collection of books that Amazon Prime members who own a kindle can borrow once a month, with no due dates.

Amazon recently launched KDP Select, a fund that lets indie authors and publishers make money off of lending. Basically, if a KDP author or publisher chooses to make any of their books exclusive to the Kindle Store for at least 90 days, those books are eligible to be included in the Kindle Owners’ Lending Library and can earn a share of the KDP Select fund.

According to the company, customers borrowed nearly 300,000 (295,000 to be exact) KDP Select titles in December alone, and KDP Select has helped grow the total library selection. With the $500,000 December fund, KDP authors have earned $1.70 per borrow. In response to strong customer adoption of the Kindle Owners’ Lending Library, Amazon says it has added a $200,000 bonus to the January KDP Select fund, raising the total pool from $500,000 to $700,000 for authors.

The top ten KDP Select authors earned over $70,000 in the month of December from their participation in the Kindle Owners’ Lending Library, which is a 30% increase on top of the royalties they earned from their paid sales on the same titles in the same period. In total (paid sales plus their share of the loan fund), these authors saw their royalties grow an astonishing 449% month-over-month from November to December. The list of top 10 KDP Select authors includes Carolyn McCray, Rachel Yu, the Grabarchuk family and Amber Scott.

As of November, the Kindle Lending Library had around 5,000 books, so clearly Amazon has seen a big jump from providing the incentive. With the release of this news, Amazon is touting the fact that independent publishers can make extra money by participating and the company is trying to convince more authors to sign on to the KDP Select program, thus increasing the number of books available for lending.