Since the first e-book platform launched in 2007, e-book sales grew to comprise 20 percent of all book sales by 2015. To ensure the increasing popularity of e-books did not undermine the success of their printed counterparts, publishers frequently delayed the digital publication date for several weeks after the print edition has been released. However, new research in the INFORMS journal Management Science found that delaying the sale of the e-version of a new book does not lead to increased print sales, and can result in significantly fewer e-book sales once the digital version is made available.