79% (1976)

79% (1978)

79% (1977)

52% (1999)

71% (1980)

81% (1976)

80% (1975)

81% (1976)

79% (1975)

70% (1974)

79% (1977)

80% (1974)

75% (1974)

76% (1974)

82% (1978)

65% (1972)

55% (1971)

77% (1975)

54% (1969)

73% (1989)