50% (1978)

39% (1982)

50% (1979)

54% (1987)

52% (1979)

47% (1989)

60% (1985)

58% (1979)

49% (1980)

45% (1979)

52% (1978)

60% (1985)

57% (1982)

53% (1977)

43% (1977)

50% (1984)

46% (1978)

46% (1991)

53% (1979)

42% (1978)