In case you missed it, author Lynn Viehl had the guts to post online her royalty statement for a book of hers that made the New York Times Bestseller list. Go read her post “The Reality of a Times Bestseller” and look over the statement for a dose of reality about book sales.
A few days ago she was kind enough to post the second royalty statement so that people can track sales over time.
Another helpful source, though it is skewed towards the romance genre, is author Brenda Hiatt’s “Show Me the Money!” web page. She’s been collecting advance and royalty data to share with Romance Writers of America members for ten years.