54% (1975)

71% (1969)

52% (1971)

69% (1974)

52% (1979)

75% (1988)

74% (1983)

81% (1982)

70% (1999)

71% (2006)

70% (2007)

71% (1986)

50% (1992)

76% (2011)

68% (1988)

84% (1983)

95% (1967)

57% (1968)

67% (1968)

70% (1996)