76% (2002)

83% (1994)

80% (1998)

76% (2000)

78% (1991)

74% (1989)

77% (1992)

75% (1997)

72% (1996)

74% (1999)

76% (2002)

73% (2003)

59% (2005)

65% (2000)

70% (1995)

70% (2001)

61% (2004)

67% (1988)

70% (1995)

68% (1990)