74% (1993)

65% (2009)

61% (1982)

59% (2007)

64% (2006)

72% (1975)

71% (1981)

66% (1992)

61% (2003)

64% (1997)

55% (1985)

67% (2008)

68% (1977)

67% (1991)

61% (2000)

58% (2007)

61% (1979)

55% (1992)

57% (2005)

66% (2009)