42% (1978)

49% (1977)

45% (1970)

47% (1962)

56% (1964)

35% (1974)

58% (1970)

67% (1973)

47% (1976)

49% (1965)

55% (1973)

67% (1963)

61% (1969)

57% (1961)

38% (1968)

50% (1976)

30% (1979)

56% (1970)

49% (1972)

52% (1980)