<P> The Big Four are the four largest professional services networks in the world, offering audit, assurance services, taxation, management consulting, advisory, actuarial, corporate finance and legal services . They handle the vast majority of audits for public companies as well as many private companies . It is reported that the Big Four audit 99% of the companies in the FTSE 100, and 96% of the companies in the FTSE 250 Index, an index of the leading mid-cap listing companies . </P> <P> The Big Four firms are shown below, with their latest publicly available data . </P> <Table> <Tr> <Th> Firm </Th> <Th> Revenues </Th> <Th> Employees </Th> <Th> Revenue per employee </Th> <Th> Fiscal year </Th> <Th> Headquarters </Th> <Th> Source </Th> </Tr> <Tr> <Td> Deloitte </Td> <Td> $38.8 bn </Td> <Td> 263,900 </Td> <Td> $147,025 </Td> <Td> 2017 </Td> <Td> United States </Td> <Td> </Td> </Tr> <Tr> <Td> PwC </Td> <Td> $35.9 bn </Td> <Td> 223,468 </Td> <Td> $160,649 </Td> <Td> 2016 </Td> <Td> United Kingdom </Td> <Td> </Td> </Tr> <Tr> <Td> EY </Td> <Td> $31.4 bn </Td> <Td> 247,570 </Td> <Td> $126,833 </Td> <Td> 2017 </Td> <Td> United Kingdom </Td> <Td> </Td> </Tr> <Tr> <Td> KPMG </Td> <Td> $25.9 bn </Td> <Td> 188,982 </Td> <Td> $134,510 </Td> <Td> 2016 </Td> <Td> Netherlands </Td> <Td> </Td> </Tr> </Table> <Tr> <Th> Firm </Th> <Th> Revenues </Th> <Th> Employees </Th> <Th> Revenue per employee </Th> <Th> Fiscal year </Th> <Th> Headquarters </Th> <Th> Source </Th> </Tr>

Where are the big four accounting firms located
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