78% (1971)

76% (1970)

70% (1972)

66% (1972)

70% (1968)

73% (1961)

65% (1974)

67% (1971)

71% (1970)

72% (1972)

64% (1965)

68% (1962)

53% (1975)

73% (1972)

79% (1971)

67% (1963)

67% (1971)

77% (1973)

52% (1966)

70% (1973)