68% (1972)

64% (1969)

65% (1965)

61% (1966)

56% (1974)

69% (1971)

63% (1971)

44% (1966)

61% (1972)

56% (1965)

54% (1977)

64% (1973)

60% (1981)

54% (1970)

62% (1974)

55% (1971)

51% (1976)

61% (1965)

50% (1967)

65% (1974)