71% (1980)

75% (1974)

71% (1976)

59% (1980)

70% (1975)

66% (1974)

64% (1979)

44% (1980)

63% (1980)

47% (1978)

63% (1975)

67% (1977)

67% (1981)

73% (1978)

50% (1977)

50% (1977)

50% (1980)

68% (1975)

66% (1973)

30% (1976)