71% (1972)

63% (1975)

60% (1976)

65% (1972)

64% (1980)

59% (1977)

61% (1976)

52% (1979)

71% (1978)

63% (1979)

67% (1975)

62% (1974)

65% (1978)

42% (1978)

55% (1977)

54% (1972)

58% (1978)

50% (1977)

58% (1972)

64% (1973)