New York (CNN Business) "Becoming" by Michelle Obama is not just one of the best-selling books of the past year — it is one of the hottest titles of the decade.

The inspirational memoir by the former first lady has been on sale for more than two months, yet it is still No. 1 on Amazon's constantly updated list of best-selling books.

Amazon said "Becoming" enjoyed the longest streak at No. 1 for any book since "Fifty Shades of Grey" came out in 2012.

No political tome or public figure's memoir has ranked No. 1 for as long as "Becoming," according to data the company provided to CNN Business.

"Becoming" was released on November 13, specifically timed to maximize holiday season sales.

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