<Table> <Tr> <Th_colspan="2"> Chicago Bulls </Th> </Tr> <Tr> <Td_colspan="2"> <Table> <Tr> <Td> </Td> <Td> 2017--18 Chicago Bulls season </Td> </Tr> </Table> </Td> </Tr> <Tr> <Td_colspan="2"> </Td> </Tr> <Tr> <Th> Conference </Th> <Td> Eastern </Td> </Tr> <Tr> <Th> Division </Th> <Td> Central </Td> </Tr> <Tr> <Th> Founded </Th> <Td> 1966 </Td> </Tr> <Tr> <Th> History </Th> <Td> Chicago Bulls 1966--present </Td> </Tr> <Tr> <Th> Arena </Th> <Td> United Center </Td> </Tr> <Tr> <Th> Location </Th> <Td> Chicago, Illinois </Td> </Tr> <Tr> <Th> Team colors </Th> <Td> Red, black </Td> </Tr> <Tr> <Th> President </Th> <Td> Michael Reinsdorf </Td> </Tr> <Tr> <Th> General manager </Th> <Td> Gar Forman </Td> </Tr> <Tr> <Th> Head coach </Th> <Td> Fred Hoiberg </Td> </Tr> <Tr> <Th> Ownership </Th> <Td> Jerry Reinsdorf </Td> </Tr> <Tr> <Th> Affiliation (s) </Th> <Td> Windy City Bulls </Td> </Tr> <Tr> <Th> Championships </Th> <Td> 6 (1991, 1992, 1993, 1996, 1997, 1998) </Td> </Tr> <Tr> <Th> Conference titles </Th> <Td> 6 (1991, 1992, 1993, 1996, 1997, 1998) </Td> </Tr> <Tr> <Th> Division titles </Th> <Td> 9 Midwest: 1 (1975) Central: 8 (1991, 1992, 1993, 1996, 1997, 1998, 2011, 2012) </Td> </Tr> <Tr> <Th> Retired numbers </Th> <Td> 4 (4, 10, 23, 33) </Td> </Tr> <Tr> <Th> Website </Th> <Td> www.nba.com/bulls </Td> </Tr> <Tr> <Th_colspan="2"> Uniforms </Th> </Tr> <Tr> <Td_colspan="2"> </Td> </Tr> <Tr> <Td_colspan="2"> <Table> <Tr> <Td> Home </Td> <Td> Away </Td> </Tr> </Table> </Td> </Tr> <Tr> <Td_colspan="2"> </Td> </Tr> </Table> <Tr> <Th_colspan="2"> Chicago Bulls </Th> </Tr>

When did chicago bulls win their first nba championship