76% (1962)

71% (1971)

66% (1974)

75% (1962)

35% (1968)

80% (1969)

64% (1980)

78% (1973)

73% (1979)

63% (1988)

90% (1990)

83% (1975)

69% (1984)

82% (1985)

75% (1977)

66% (1968)

55% (1987)

70% (1978)

78% (1980)

59% (1985)