79% (1964)

78% (1987)

68% (1973)

67% (1976)

63% (1982)

73% (1975)

63% (1974)

77% (1992)

73% (1994)

77% (1986)

74% (1995)

67% (1986)

67% (1997)

64% (1978)

72% (1990)

69% (1984)

71% (1984)

66% (1985)

66% (1954)

68% (1985)