<Tr> <Td> 11 September 2017 (Monday) </Td> <Td> Advance voting begins </Td> </Tr> <Tr> <Td> 22 September 2017 (Friday) </Td> <Td> Advance voting ends; overseas voting ends at 16: 00 local time . Last day to enrol to vote . The regulated election advertising period ends; all election advertising must be taken down by midnight . </Td> </Tr> <Tr> <Td> 23 September 2017 (Saturday) </Td> <Td> Election day--polling places open 09: 00 to 19: 00 Preliminary results released progressively after 19: 00 </Td> </Tr> <Tr> <Td> 7 October 2017 (Saturday) </Td> <Td> Official results declared </Td> </Tr>

The average voting swing in 2017-8 special house elections indicates that