All Available Season All Season Season 1 Sep, 1972 22 episodes 8.0 Season 2 Sep, 1973 24 episodes 0.0 Season 3 Sep, 1974 23 episodes 8.0 Season 4 Sep, 1975 24 episodes 7.7 Season 5 Sep, 1976 24 episodes 7.6 Season 6 Sep, 1977 24 episodes 1.0
