74% (1974)

71% (1980)

70% (1976)

70% (1975)

66% (1974)

67% (1977)

68% (1975)

59% (1980)

64% (1979)

67% (1981)

44% (1980)

54% (1980)

62% (1980)

50% (1977)

73% (1978)

63% (1975)

47% (1978)

67% (1973)

50% (1980)

50% (1977)