71% (1969)

70% (1977)

64% (1973)

65% (1970)

58% (1969)

67% (1969)

53% (1971)

55% (1969)

50% (1969)

59% (1972)

49% (1975)

50% (1976)

50% (1970)

61% (1968)

48% (1970)

58% (1975)

45% (1974)

55% (1969)

66% (1976)

50% (1973)