74% (1977)

80% (1978)

72% (1974)

70% (1983)

72% (1978)

64% (1978)

72% (1978)

60% (1977)

71% (1977)

69% (1982)

62% (1980)

69% (1982)

60% (1976)

55% (1980)

59% (1979)

67% (1970)

64% (1982)

67% (1983)

56% (1971)

48% (1983)