57% (1965)

57% (1974)

55% (1971)

60% (1972)

54% (1977)

64% (1965)

59% (1965)

50% (1976)

62% (1974)

59% (1973)

57% (1970)

62% (1966)

54% (1970)

69% (1971)

63% (1971)

64% (1973)

62% (1966)

50% (1967)

68% (1972)

59% (1981)