70% (1990)

80% (1996)

73% (1993)

68% (1994)

70% (1995)

71% (1997)

72% (1992)

72% (1998)

76% (1996)

73% (1996)

69% (1998)

67% (1985)

66% (1999)

62% (1994)

71% (1990)

63% (1988)

70% (1990)

57% (1993)

62% (1998)

50% (1985)