62% (1974)

65% (1963)

56% (1964)

39% (1958)

67% (1973)

52% (1960)

50% (1974)

59% (1968)

57% (1974)

46% (1977)

55% (1970)

46% (1958)

41% (1956)

54% (1966)

53% (1970)

50% (1966)

47% (1977)

48% (1972)

64% (1973)

50% (1964)