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An employee selects goods from bays of merchandise as she processes customer orders at the Amazon.com Inc. fulfillment center in Poznan, Poland, on Friday, June 12, 2015. Amazon is the largest distributor of e-books in Europe, where the product's popularity has experienced a surge in recent years. Photographer: Bartek Sadowski/Bloomberg via Getty Images

An employee selects goods from bays of merchandise as she processes customer orders at the Amazon.com Inc. fulfillment center in Poznan, Poland, on Friday, June 12, 2015. Amazon is the largest distributor of e-books in Europe, where the product's popularity has experienced a surge in recent years. Photographer: Bartek Sadowski/Bloomberg via Getty Images