The book, which was released on November 13, has already sold more than 2 million copies in the U.S. and Canada across all formats. The hardcover edition alone has sold more copies than any other book in the U.S. tin 2018.

In the U.S. and Canada, Becoming is already in its sixth printing, with 3.4 million copies in print. But the book’s—and author’s—popularity are not limited to North America. Becoming is also the No. 1 seller in the U.K., Germany, France, Italy, Holland, Spain, Denmark, Norway, Finland, and Greece and is being published in 31 languages.

The book has become a mainstay on a number of lists, remaining at No. 1 on two New York Times bestseller lists, as well as topping bestseller lists from USA Today and Publishers Weekly.

The popularity of the book is a testament to the popularity of the former first lady. Former first lady Hillary Clinton’s memoir Living History, for example, took one month to sell 1 million copies. And even the books of former presidents have not performed as well as Becoming.

Former President George W. Bush’s Decision Points took several weeks to sell 2 million, while former President Bill Clinton’s My Life hit the 1 million mark quickly, but then took much longer to sell 2 million copies.

Obama is currently on a multi-city U.S. book tour, selling out theaters and stadiums. She will interrupt the tour next week to make several appearances to sold-out crowds in Europe.