77% (1997)

79% (1987)

77% (1992)

79% (1990)

79% (1997)

74% (1974)

66% (1970)

56% (1975)

73% (1989)

71% (1984)

76% (1991)

55% (1995)

59% (1982)

61% (1972)

72% (1976)

62% (1973)

65% (1974)

65% (1979)

52% (1976)

58% (2000)