65% (1975)

72% (1976)

62% (1973)

71% (1970)

70% (1967)

70% (1972)

61% (1972)

53% (1971)

67% (1973)

72% (1971)

57% (1973)

69% (1971)

55% (1971)

71% (1974)

70% (1974)

67% (1975)

58% (1972)

67% (1973)

58% (1977)

54% (1970)