A self-supporting government enterprise, the U.S. Postal Service is the only delivery service that reaches every address in the nation: 152 million residences, businesses and Post Office Boxes. The Postal Service receives no tax dollars for operating expenses and relies on the sale of postage, products and services to fund its operations. With more than 31,000 retail locations and the most frequently visited website in the federal government, usps.com, the Postal Service has annual revenue of more than $65 billion and delivers nearly 40 percent of the world's mail. If it were a private-sector company, the U.S. Postal Service would rank 42nd in the 2012 Fortune 500. The Postal Service has been named the Most Trusted Government Agency for seven years and the fourth Most Trusted Business in the nation by the Ponemon Institute.