Michelle Obama’s book has sold almost 10 million copies, on track toward a historic high for memoirs

Michelle Obama’s publisher said that her book “Becoming” has sold almost 10 million copies and could be the most successful memoir in history, Bloomberg reported Tuesday.

The success of the former first lady’s book helped German media company Bertelsmann SE, which owns American mega-publisher Penguin Random House, earn $20 billion in revenue last year, the most it’s taken in since 2007.

Penguin Random House CEO Markus Dohle said Obama’s book could become a “modern classic” and added that he hopes former President Obama’s forthcoming book, as yet untitled and with no projected release date, will meet with the same success. Earlier this month, the former president said he was “at the tail end” of writing his memoir.

“Becoming” became a publishing phenomenon almost instantly after its release last November. It is the No. 1 hardcover nonfiction bestseller on the New York Times’ list, where it has spent 18 weeks. And as of Tuesday morning, it was the No. 4 bestselling book on Amazon.

The book drew positive reviews from critics and is a finalist for the Los Angeles Times Book Prize for Current Interest, along with books like Michael Lewis’ “The Fifth Risk” and Susan Orlean’s “The Library Book.”

Penguin Random House bet heavily on the projected success of books by Michelle Obama and her husband, giving the couple a two-book deal speculated to be worth $60 million.

Obama has embarked on a long book tour to promote “Becoming,”appearing at arenas and other large venues. Tickets to her events routinely sell out quickly.

On Sunday, she spoke to more than 18,000 people — her largest crowd yet — at a stadium in Tacoma, Wash. Talk show host Jimmy Kimmel moderated the event, which featured appearances by Pearl Jam frontman Eddie Vedder and singer-songwriter Ciara.

Obama still has 11 stops scheduled for her tour, including appearances in Europe, Canada and the United States. Her final stop will be at the Ryman Auditorium in Nashville, Tenn., where she’ll be joined by talk show host Stephen Colbert. Tickets to that event have already sold out.