72% (1974)

72% (1978)

80% (1978)

74% (1977)

69% (1982)

71% (1977)

63% (1978)

70% (1983)

72% (1978)

60% (1976)

56% (1971)

61% (1977)

63% (1982)

60% (1970)

68% (1971)

58% (1978)

67% (1970)

62% (1980)

62% (1978)

55% (1980)