There will be over 285 million big brand tablets in use by the end of the year, a new report from ABI Research shows, from well-known devices makers including Apple, Samsung and others. Apparently the report does not include cheaper tablets made by less known players in the tablet business, also known as white-box tablets. In the U.S., more than 70 million tablets will have been purchased by the end of the year, “about one for every four persons.”