<Tr> <Td> Mining </Td> <Td> 800,500 </Td> </Tr> <Tr> <Td> Oil and gas extraction </Td> <Td> 192,300 </Td> </Tr> <Tr> <Td> Mining, except oil and gas </Td> <Td> 204,900 </Td> </Tr> <Tr> <Td> Coal mining </Td> <Td> 78,200 </Td> </Tr>

What is the largest employment sector in the united states