43% (1977)

50% (1984)

58% (1977)

58% (1978)

45% (1982)

50% (1983)

50% (1982)

49% (1980)

45% (1979)

37% (1985)

60% (1985)

58% (1979)

54% (1987)

50% (1982)

52% (1979)

46% (1991)

45% (1980)

50% (1978)

42% (1978)

49% (1980)