The full article is here, with links to download their slideshow.
But if you just want the headlines they are:
$2.99 and $3.99 are the sweet spots for most of the bestsellers. Free still works great, but it's losing some mojo.
Readers prefer longer ebooks.
Preorders yield sales advantage.
Series yield sales advantage.
Best-performing series have longer books.
Series that have free series starters earn more money for authors than series that do not.
Non-fiction earns more at higher prices.
Be cautious. Survey results are based on averages.
Helen is available to line edit and/ or content edit fiction and non-fiction. Rates on application.