72% (1972)

60% (1976)

64% (1980)

65% (1972)

63% (1975)

62% (1979)

62% (1976)

65% (1978)

69% (1975)

52% (1979)

72% (1978)

59% (1977)

53% (1972)

58% (1972)

56% (1977)

58% (1978)

55% (1977)

61% (1974)

42% (1978)

48% (2017)