88% (1994)

86% (1999)

73% (2007)

80% (1995)

80% (2010)

67% (2011)

66% (2000)

67% (2004)

64% (2002)

56% (1996)

70% (1993)

75% (1989)

78% (1990)

68% (2003)

67% (2007)

58% (2005)

79% (2004)

64% (2010)

76% (2013)

68% (2007)