71% (1980)

75% (1974)

67% (1977)

67% (1974)

71% (1976)

59% (1980)

45% (1980)

68% (1975)

66% (1981)

64% (1979)

62% (1975)

74% (1978)

45% (1977)

62% (1980)

50% (1980)

47% (1978)

62% (1973)

30% (1976)

50% (1977)

54% (1980)