<Table> United States Department of Defense <Tr> <Td_colspan="2"> </Td> </Tr> <Tr> <Th_colspan="2"> Department overview </Th> </Tr> <Tr> <Th> Formed </Th> <Td> September 18, 1947; 70 years ago (1947 - 09 - 18) (as National Military Establishment) </Td> </Tr> <Tr> <Th> Preceding Department </Th> <Td> <Ul> <Li> U.S. Department of the Army U.S. Department of the Navy U.S. Department of the Air Force </Li> </Ul> </Td> </Tr> <Tr> <Th> Type </Th> <Td> Executive Department </Td> </Tr> <Tr> <Th> Headquarters </Th> <Td> The Pentagon Arlington County, Virginia, United States 38 ° 52 ′ 16" N 77 ° 3 ′ 21" W ﻿ / ﻿ 38.87111 ° N 77.05583 ° W ﻿ / 38.87111; - 77.05583 Coordinates: 38 ° 52 ′ 16" N 77 ° 3 ′ 21" W ﻿ / ﻿ 38.87111 ° N 77.05583 ° W ﻿ / 38.87111; - 77.05583 </Td> </Tr> <Tr> <Th> Employees </Th> <Td> <P> 742,000 (civilian) 1,300,000 (active duty military) 826,000 (National Guard and reserve): </P> 2.87 million total (2016) </Td> </Tr> <Tr> <Th> Annual budget </Th> <Td> US $530.1 billion (2010) US $549.1 billion (2011) US $553.0 billion (est. 2012) US $496.1 billion (2015) US $534.3 billion (base FY2016) </Td> </Tr> <Tr> <Th> Department executives </Th> <Td> <Ul> <Li> Jim Mattis, Secretary </Li> <Li> Patrick M. Shanahan, Deputy Secretary </Li> </Ul> </Td> </Tr> <Tr> <Th> Child agencies </Th> <Td> <Ul> <Li> U.S. Department of the Army </Li> <Li> U.S. Department of the Navy </Li> <Li> U.S. Department of the Air Force </Li> </Ul> </Td> </Tr> <Tr> <Th> Website </Th> <Td> www.defense.gov </Td> </Tr> </Table> <Tr> <Th_colspan="2"> Department overview </Th> </Tr>

When was the us department of defense established