82% (1973)

51% (1977)

64% (1987)

59% (1982)

70% (1980)

57% (1985)

63% (1978)

73% (1987)

84% (1980)

76% (1977)

82% (1975)

82% (1978)

70% (1980)

63% (1988)

77% (1985)

67% (1988)

74% (1981)

45% (1990)

78% (1974)

63% (1961)