66% (1968)

68% (1993)

76% (2001)

75% (1997)

67% (1992)

67% (2010)

82% (2011)

80% (1986)

54% (1996)

61% (1991)

61% (1983)

67% (1994)

71% (1994)

51% (1998)

84% (1957)

69% (2009)

86% (1997)

77% (1987)

79% (2002)

79% (2006)