82% (2006)

74% (2002)

76% (2006)

73% (2004)

71% (2000)

68% (2001)

61% (2007)

68% (2005)

63% (1998)

58% (2004)

66% (2002)

52% (2008)

62% (2005)

72% (1998)

57% (1998)

48% (1997)

50% (2007)

52% (1999)

65% (1997)

57% (1991)