74% (1986)

70% (1987)

69% (1990)

70% (1987)

61% (1991)

58% (1989)

72% (1989)

58% (1988)

61% (1985)

51% (1989)

51% (1990)

50% (1983)

58% (1987)

71% (1988)

62% (1988)

64% (1988)

65% (1988)

62% (1987)

53% (1988)

58% (1990)