81% (1981)

70% (1978)

63% (1987)

60% (1987)

37% (1976)

70% (1981)

50% (1984)

37% (1979)

63% (1988)

73% (1984)

70% (1981)

82% (1984)

70% (1979)

67% (1980)

65% (1988)

63% (1989)

63% (1984)

60% (1988)

57% (1981)

68% (1975)