54% (1970)

57% (1967)

63% (1972)

47% (1962)

45% (1977)

50% (1976)

51% (1980)

68% (1964)

72% (1965)

44% (1976)

58% (1965)

55% (1970)

49% (1965)

66% (1973)

58% (1976)

58% (1969)

55% (1963)

64% (1973)

49% (1964)

54% (1970)