72% (1972)

65% (1972)

61% (1976)

62% (1979)

64% (1980)

62% (1976)

63% (1975)

59% (1977)

72% (1978)

69% (1975)

53% (1979)

61% (1974)

58% (1972)

56% (1977)

54% (1972)

55% (1977)

47% (1978)

58% (1978)

65% (1978)

64% (1973)