78% (1984)

67% (1987)

79% (1989)

78% (1994)

69% (1998)

68% (2008)

76% (2000)

68% (2007)

62% (2012)

66% (2009)

66% (1994)

69% (2005)

62% (1995)

60% (1998)

64% (2009)

51% (2008)

51% (2009)

50% (1993)

74% (2001)

68% (2008)