77% (1997)

80% (1987)

80% (1997)

77% (1992)

79% (1990)

74% (1974)

76% (1991)

71% (1984)

73% (1989)

66% (1970)

57% (1975)

55% (1995)

58% (2000)

54% (1975)

67% (1996)

65% (1979)

72% (1976)

60% (1972)

50% (1983)

61% (1972)