57% (1966)

64% (1968)

61% (1972)

68% (1972)

59% (1967)

65% (1969)

45% (1970)

52% (1969)

49% (1970)

60% (1968)

63% (1967)

64% (1971)

53% (1971)

59% (1961)

42% (1968)

48% (1969)

55% (1973)

60% (1972)

39% (1973)

43% (1984)