<Tr> <Td> </Td> <Td_colspan="1"> </Td> <Td> Riders of Berk </Td> <Td_colspan="2"> 20 </Td> <Td_colspan="1"> August 7, 2012 (2012 - 08 - 07) </Td> <Td> March 20, 2013 (2013 - 03 - 20) </Td> </Tr> <Tr> <Td> </Td> <Td_colspan="1"> </Td> <Td> Defenders of Berk </Td> <Td_colspan="2"> 20 </Td> <Td_colspan="1"> September 19, 2013 (2013 - 09 - 19) </Td> <Td> March 5, 2014 (2014 - 03 - 05) </Td> </Tr> <Table> Netflix episodes <Tr> <Th_colspan="2"> Season </Th> <Th> Subtitle </Th> <Th_colspan="2"> Episodes </Th> <Th_colspan="2"> Originally released </Th> </Tr> <Tr> <Td> </Td> <Td_colspan="1"> </Td> <Td> Race to the Edge </Td> <Td_colspan="2"> 13 </Td> <Td_colspan="1"> June 26, 2015 (2015 - 06 - 26) </Td> </Tr> <Tr> <Td> </Td> <Td_colspan="1"> </Td> <Td_colspan="2"> 13 </Td> <Td_colspan="1"> January 8, 2016 (2016 - 01 - 08) </Td> </Tr> <Tr> <Td> </Td> <Td_colspan="1"> </Td> <Td_colspan="2"> 13 </Td> <Td_colspan="1"> June 24, 2016 (2016 - 06 - 24) </Td> </Tr> <Tr> <Td> </Td> <Td_colspan="1"> </Td> <Td_colspan="2"> 13 </Td> <Td_colspan="1"> February 17, 2017 (2017 - 02 - 17) </Td> </Tr> <Tr> <Td> </Td> <Td_colspan="1"> 5 </Td> <Td_colspan="2"> 13 </Td> <Td_colspan="1"> August 25, 2017 (2017 - 08 - 25) </Td> </Tr> </Table> <Tr> <Th_colspan="2"> Season </Th> <Th> Subtitle </Th> <Th_colspan="2"> Episodes </Th> <Th_colspan="2"> Originally released </Th> </Tr>

How many seasons of dragons race to the edge