70% (1977)

70% (1969)

66% (1970)

64% (1973)

59% (1972)

61% (1968)

54% (1972)

58% (1969)

65% (1970)

56% (1969)

62% (1968)

58% (1975)

49% (1975)

49% (1974)

53% (1971)

66% (1976)

54% (1974)

68% (1976)

52% (1970)

53% (1969)