53% (1977)

56% (1974)

50% (1964)

40% (1961)

55% (1972)

66% (1973)

55% (1966)

38% (1971)

52% (1971)

48% (1969)

45% (1968)

56% (1977)

57% (1959)

46% (1971)

40% (1965)

38% (1955)

67% (1975)

47% (1958)

54% (1970)

58% (1969)