64% (1978)

74% (1978)

52% (1978)

57% (1985)

27% (1979)

59% (1977)

58% (1979)

39% (1982)

51% (1978)

72% (1981)

53% (1979)

58% (1977)

60% (1985)

63% (1977)

54% (1987)

43% (1977)

72% (1988)

50% (1979)

54% (1990)

46% (1991)