73% (1973)

57% (1974)

62% (1976)

43% (1970)

50% (1974)

64% (1976)

63% (1971)

62% (1980)

60% (1987)

38% (1972)

62% (1968)

49% (1975)

69% (1979)

32% (1972)

65% (1972)

67% (1986)

58% (1977)

49% (1977)

40% (1981)

54% (1968)