I have done a bit of research into the Amazon Sales Rank and the results are surprising.
ASR Books Sold per week
------ -----------------
75-100 ----------- 250-275/wk
100-200 ---------- 225-249/wk
200-300 ---------- 150-200/wk
450-750 ---------- 75-100/wk
750-3,000 -------- 40-75/wk
3,000-9,000 ------ 15-20/wk
10,000+ ---------- 1-5/wk
The author remains the main component in the mix --- Great works sell themselves while poorly-conceived and badly written books fester on the shelves, damaging the reputation of the author and the publisher who was gullible enough to publish rubbish.
Every publisher wants to get a bestseller but the reality is that a runaway-bestseller is a very rare event for any publisher.
What makes a bestseller?
The bestseller "On Bullshit" has an Amazon Sales Rank of 14, translating into sales of more than 2,000 copies per month! Why?
Well, the book is a hardcover edition (which is perceived as gift-quality by the consumer), and it is very cheap ($5.97 on Amazon).
The book “On Bullshit” became a bestseller gift-book for its naughty-word title and the price/value ratio, nothing more. Nonetheless, it’s a superb piece of marketing where a publisher took a piece of academic ruminations and turned it into a hot book.
The First American Bestseller
Word-of-mouth is also a great factor in book sales. Consider Thomas Paine's bestseller "Common Sense", first published in 1775. The only publisher who agreed to print it wanted half the book revenue, and Paine agreed to donate his profits to supply mittens for the Revolutionary Soldiers who were attacking Quebec.
The “Common Sense” book sold over 20,000 copies in the first 90-days, and eventually over 500,000 copies. Even today, 225 years later, "Common Sense" has a respectable Amazon Sales Rank of 20,000, about one copy per day.
Click here to read my research on the Amazon Sales Rank.