74% (1978)

49% (1980)

57% (1985)

72% (1981)

45% (1980)

64% (1978)

50% (1982)

72% (1988)

27% (1979)

59% (1977)

42% (1982)

58% (1977)

58% (1978)

52% (1977)

54% (1990)

53% (1979)

63% (1977)

50% (1982)

50% (1983)

51% (1978)