All Available Season All Season Season 1 Sep, 1972 24 episodes 7.5 Season 2 Sep, 1973 24 episodes 7.8 Season 3 Sep, 1974 24 episodes 7.6 Season 4 Sep, 1975 24 episodes 7.8 Season 5 Sep, 1976 24 episodes 7.7 Season 6 Sep, 1977 24 episodes 7.8 Season 7 Sep, 1978 25 episodes 7.8 Season 8 Sep, 1979 25 episodes 7.9 Season 9 Nov, 1980 20 episodes 7.7 Season 10 Oct, 1981 21 episodes 7.4 Season 11 Oct, 1982 16 episodes 7.4
