58% (1971)

77% (1988)

74% (1985)

76% (1984)

74% (1981)

68% (1969)

62% (1971)

76% (1984)

77% (1982)

61% (1980)

64% (1973)

70% (1986)

68% (1967)

65% (1973)

71% (1987)

55% (1986)

53% (1977)

71% (1982)

70% (1980)

56% (1976)