<Tr> <Td> Professional and technical services </Td> <Td> 8,012,800 </Td> </Tr> <Tr> <Td> Legal services </Td> <Td> 1,122,800 </Td> </Tr> <Tr> <Td> Accounting and bookkeeping services </Td> <Td> 989,300 </Td> </Tr> <Tr> <Td> Architectural and engineering services </Td> <Td> 1,314,000 </Td> </Tr>

What entity is the largest single employer in the us