71% (1972)

52% (1979)

64% (1980)

58% (1978)

72% (1978)

69% (1975)

59% (1972)

65% (1978)

63% (1979)

61% (1976)

64% (1972)

61% (1974)

56% (1977)

63% (1975)

53% (1972)

60% (1977)

42% (1978)

58% (1977)

61% (1976)

50% (1977)