74% (1977)

80% (1978)

64% (1978)

72% (1974)

69% (1982)

72% (1978)

70% (1983)

61% (1980)

72% (1977)

72% (1978)

69% (1984)

67% (1983)

68% (1971)

62% (1976)

61% (1977)

58% (1979)

58% (1978)

59% (1980)

67% (1970)

56% (1971)