64% (1975)

65% (1984)

70% (1975)

70% (1977)

80% (1979)

70% (1981)

70% (1978)

60% (1988)

73% (1983)

65% (1976)

75% (1980)

62% (1983)

72% (1987)

70% (1982)

70% (1978)

40% (1987)

60% (1989)

73% (1987)

63% (1974)

78% (1981)