Also, Amazon sells many products from many different brands and companies. Customers are the most important thing to Amazon, and Amazon knows that delivery service is one thing customers want most. The way Amazon meets customer satisfaction with its delivery service is by having 55 fulfillment centers located in North America. Because fulfillment centers are not retail stores, Amazon products are not required to charge sales tax. In addition to Amazon's 53 fulfillment centers in North America, Amazon also has 53 distribution centers in Europe, Japan, Asia and India. Since Amazon has many warehouses in many different locations, it can reach its customers more conveniently. Amazon's growth over the years has allowed its company to reduce costs. In addition to being one of the best online shopping sites, Amazon also developed the Kindle, which is now one of the most popular e-reader tablets around.