73% (1981)

71% (1982)

73% (1988)

70% (1988)

70% (1973)

64% (1979)

62% (1977)

61% (1980)

57% (1990)

69% (1983)

72% (1975)

60% (1984)

64% (1976)

62% (1985)

60% (1974)

60% (1987)

53% (1972)

60% (1984)

33% (1981)

66% (1976)