59% (1977)

72% (1988)

54% (1993)

50% (1979)

57% (1986)

62% (1974)

57% (1981)

41% (1990)

62% (1974)

50% (1973)

48% (1975)

59% (1979)

67% (1985)

56% (1993)

69% (1975)

38% (1990)

52% (1994)

54% (1993)

45% (1990)

41% (1982)