79% (1994)

77% (1986)

76% (2001)

74% (1999)

81% (1994)

75% (1996)

63% (1985)

64% (2000)

65% (1997)

69% (2008)

62% (1980)

71% (1992)

66% (2001)

67% (2004)

54% (1982)

62% (1986)

68% (1993)

60% (2009)

46% (2010)

62% (1987)