<Tr> <Th> Fiscal year </Th> <Td> 1 April--31 March (government); 1 March--28 / 29 February (corporate & private) </Td> </Tr> <Tr> <Th> Trade organisations </Th> <Td> WTO, G - 20, SACU and others </Td> </Tr> <Tr> <Th_colspan="2"> Statistics </Th> </Tr> <Tr> <Th> GDP </Th> <Td> <P> $280.37 billion (2017 est .) (nominal; List of countries by GDP (nominal)) </P> $758.12 billion (2017 est .) (PPP; List of countries by GDP (PPP)) </Td> </Tr>

Identify and describe four factors that fluctuate the economy of south africa