71% (1978)

72% (1980)

81% (1974)

79% (1975)

82% (1977)

79% (1976)

80% (1975)

81% (1976)

80% (1977)

79% (1978)

76% (1975)

84% (1973)

54% (2000)

71% (1979)

76% (1983)

78% (1975)

76% (1974)

66% (1979)

30% (2006)

71% (1975)