<Tr> <Th> Season </Th> <Th> Timeslot (ET) </Th> <Th> Episodes </Th> <Th_colspan="2"> First aired </Th> <Th_colspan="2"> Last aired </Th> <Th> TV season </Th> <Th> Rank </Th> <Th> Avg . viewers (millions) </Th> <Th> 18--49 rating (average) </Th> </Tr> <Tr> <Th> Date </Th> <Th> Viewers (millions) </Th> <Th> Date </Th> <Th> Viewers (millions) </Th> </Tr> <Tr> <Td> </Td> <Td> Thursday 9: 00 pm </Td> <Td> 13 </Td> <Td> January 26, 2017 (2017 - 01 - 26) </Td> <Td> 1.38 </Td> <Td> May 11, 2017 (2017 - 05 - 11) </Td> <Td> 0.96 </Td> <Td> 2016--17 </Td> <Td> 154 </Td> <Td> 1.69 </Td> <Td> 0.7 / 2 </Td> </Tr> <Tr> <Td> </Td> <Td> Wednesday 8: 00 pm </Td> <Td> 22 </Td> <Td> October 11, 2017 (2017 - 10 - 11) </Td> <Td> 2.34 </Td> <Td> TBA </Td> <Td> TBD </Td> <Td> 2017--18 </Td> <Td> TBD </Td> <Td> TBD </Td> <Td> TBD </Td> </Tr>

How old are the riverdale characters in the show