73% (1976)

72% (1972)

53% (1971)

65% (1975)

71% (1971)

70% (1967)

56% (1973)

66% (1975)

66% (1973)

70% (1974)

71% (1970)

69% (1971)

69% (1974)

58% (1974)

62% (1973)

74% (1971)

69% (1976)

66% (1973)

63% (1975)

66% (1977)