68% (1974)

48% (1960)

55% (1967)

42% (1958)

44% (1967)

56% (1975)

65% (1963)

61% (1965)

58% (1977)

37% (1970)

66% (1969)

71% (1965)

50% (1962)

62% (1964)

64% (1976)

47% (1968)

56% (1972)

62% (1966)

44% (1973)

54% (1961)