69% (1983)

72% (1975)

64% (1979)

64% (1976)

62% (1985)

70% (1973)

61% (1980)

67% (1976)

72% (1981)

73% (1988)

60% (1984)

62% (1974)

67% (1988)

71% (1982)

60% (1987)

34% (1981)

62% (1977)

57% (1990)

52% (1972)

0% (1990)