<Tr> <Th> Ownership </Th> <Td> Boston Basketball Partners (Wyc Grousbeck, CEO and governor) </Td> </Tr> <Tr> <Th> Affiliation (s) </Th> <Td> Maine Red Claws </Td> </Tr> <Tr> <Th> Championships </Th> <Td> 17 (1957, 1959, 1960, 1961, 1962, 1963, 1964, 1965, 1966, 1968, 1969, 1974, 1976, 1981, 1984, 1986, 2008) </Td> </Tr> <Tr> <Th> Conference titles </Th> <Td> 21 (1957, 1958, 1959, 1960, 1961, 1962, 1963, 1964, 1965, 1966, 1968, 1969, 1974, 1976, 1981, 1984, 1985, 1986, 1987, 2008, 2010) </Td> </Tr>

When was the last time celtics won nba championship