51% (1978)

59% (1977)

52% (1978)

72% (1981)

50% (1984)

74% (1978)

39% (1982)

72% (1988)

57% (1985)

52% (1977)

42% (1982)

47% (1982)

49% (1980)

50% (1979)

47% (1989)

49% (1980)

54% (1987)

52% (1979)

45% (1980)

58% (1979)