52% (1987)

52% (1988)

55% (1980)

54% (1985)

59% (1989)

66% (1987)

45% (1990)

40% (1990)

47% (1986)

58% (1991)

50% (1988)

38% (1989)

53% (1986)

44% (1986)

40% (1982)

48% (1988)

42% (1990)

51% (1988)

46% (1985)

43% (1987)