Amazon released some new figures about the success of the Kindle Direct Publishing (KDP) Select program, which launched in December. The retail giant says that the Kindle E-Book Lending Library now features over 75,000 titles, and demand is on the rise thanks to KDP Select.

Customers are allowed to borrow one book per month, and in December 295,000 KDP Select books have been lend by Amazon. This growth drove the company to increase funding to the program by $200,000 to a monthly $700,000.

“KDP Select appears to be earning authors more money in two ways. We knew customers would love having KDP Select titles in the Kindle Owners’ Lending Library. But we’ve been surprised by how much paid sales of those same titles increased, even relative to the rest of KDP,” said Russ Grandinetti, Vice President of Kindle Content. “Due to this early success and a seasonally strong January, we’re adding a $200,000 bonus to January’s KDP Select fund, growing this month’s total pool to $700,000.”

Authors earned $1.70 per borrow, and the top 10 ones that selected to market their books via KDP Select have seen a 30 percent increase in income compared to their November earnings.

The program has proved to be a good investment on behalf of Amazon, but it’s not the only driver behind a growth in e-book borrowing and purchasing. The Kindle Fire has become extremely popular throughout the holiday season and beyond, and that momentum is only growing. WiFi network operator JiWire reported that the number of connected Kindle Fires more than tripled after the holidays, with Denver and Los Angeles leading the connectivity growth chart. Millennial has also seen growth on its ad network, and said on Dec 20 that Kindle Fire impressions increased 19 percent since launch.