77% (1997)

79% (1997)

79% (1987)

80% (1990)

77% (1992)

71% (1984)

73% (1989)

76% (1991)

72% (1976)

73% (1974)

66% (1970)

56% (1975)

61% (1972)

62% (1973)

58% (2000)

65% (1979)

55% (1975)

67% (1996)

55% (1995)

50% (1975)