<Table> United States Postal Service <Tr> <Td_colspan="2"> Logo used since 1993 </Td> </Tr> <Tr> <Td_colspan="2"> USPS headquarters </Td> </Tr> <Tr> <Th_colspan="2"> Agency overview </Th> </Tr> <Tr> <Th> Formed </Th> <Td> July 1, 1971; 46 years ago (1971 - 07 - 01) Washington, D.C., U.S. </Td> </Tr> <Tr> <Th> Type </Th> <Td> Independent </Td> </Tr> <Tr> <Th> Headquarters </Th> <Td> 475 L'Enfant Plaza SW Washington, D.C. 20260 - 0004 </Td> </Tr> <Tr> <Th> Employees </Th> <Td> 639,789 (508,908 career, 130,881 non-career) as of September 30, 2016 </Td> </Tr> <Tr> <Th> Agency executives </Th> <Td> <Ul> <Li> Megan Brennan, Postmaster General </Li> <Li> Ronald A. Stroman, Deputy Postmaster General and Chief Government Relations Officer </Li> <Li> James (Jim) P. Cochrane, Chief Customer and Marketing Officer and Executive Vice President </Li> <Li> David E. Williams, Chief Operating Officer and Executive Vice President </Li> </Ul> </Td> </Tr> <Tr> <Th> Key document </Th> <Td> <Ul> <Li> Postal Clause of the United States Constitution </Li> </Ul> </Td> </Tr> <Tr> <Th> Website </Th> <Td> www.usps.com </Td> </Tr> </Table> <Tr> <Td_colspan="2"> Logo used since 1993 </Td> </Tr>

When did the united states postal service start