53% (1977)

51% (1987)

60% (1975)

47% (1978)

55% (1977)

54% (1988)

38% (1985)

58% (1984)

48% (1976)

49% (1989)

55% (1977)

66% (1968)

59% (1987)

95% (1996)

53% (1998)

45% (1980)

48% (1982)

52% (1985)

55% (1988)

50% (1986)