First, courtesy of the way back machine, here is the rating breakdown as of 10:31am:
... As of 14:55pm
... and what it looks like right now: over 97% of the reviews are now 5 star, with over 1,000 reviews deleted. As of 5:30pm, of the 445 total review, 438 reviews were positive, and 7 (as of 5:30pm_ were critical. The latter number inexplicably keeps doing down.
To be sure, one can claim that neither the 1-star nor the 5-star reviews are legitimate, and were merely a partisan effort seeking to amass an either extremely negative or positive view of Clinton's book, however Amazon's decision to engage in a wholesale deletion of what appears to be uniformly low ratings will likely raise at least a few eyebrows.
Readers can observe the historical changes to Amazon's "What Happened" page on their own thanks to the Way Back Machine.