78% (1986)

72% (1985)

69% (1986)

71% (1986)

65% (1986)

53% (1987)

60% (1989)

55% (1983)

56% (1989)

57% (1990)

55% (1988)

61% (1991)

59% (1991)

49% (1986)

57% (1990)

61% (1987)

64% (1990)

67% (1987)

39% (1990)