78% (1981)

74% (1987)

58% (1973)

81% (1981)

73% (1984)

70% (1977)

72% (1978)

64% (1975)

65% (1984)

80% (1979)

37% (1976)

73% (1985)

40% (1987)

60% (1988)

70% (1981)

80% (1981)

67% (1989)

75% (1984)

70% (1975)

60% (1989)