62% (1982)

74% (1993)

65% (2009)

63% (2006)

61% (2003)

71% (1981)

73% (1975)

66% (1992)

59% (2007)

64% (1997)

61% (2000)

67% (1977)

66% (2009)

68% (2008)

52% (1994)

61% (1979)

55% (1985)

62% (2007)

66% (1991)

58% (2005)