74% (1974)

72% (1980)

67% (1981)

71% (1976)

44% (1980)

60% (1980)

64% (1979)

74% (1978)

70% (1975)

66% (1974)

48% (1977)

62% (1975)

67% (1977)

50% (1980)

68% (1975)

62% (1973)

62% (1980)

47% (1978)

30% (1976)

50% (1977)