With revenue of more than $70 million, the United States Postal Service is an independent establishment of the executive branch of the United States government. It serves individual and commercial customers throughout the U.S. The postal service operates a strategic planning office that is responsible for managing its day-to-day functions. It operates a research and development facility for the design, development and testing of postal equipment and operating systems, as well as contracts with independent suppliers to conduct research activities. Established in 1971, the United States Postal Service work force focuses on the movement of messages and merchandise throughout the world. It also provides retail services through over 4,000 contract postal units and community post offices. The postal service has been one of the environmental leaders through a variety of policies, programs and initiatives, including recycling and pressure-sensitive stamps. The United States Postal Service maintains nearly 37,000 post offices, stations, branches, contract postal units and a large network of consignees. It maintains a presence in Chicago.