81% (1959)

76% (1962)

73% (1968)

78% (1973)

69% (1975)

63% (1967)

71% (1981)

72% (1970)

78% (1969)

71% (1979)

73% (1980)

72% (1968)

72% (1976)

73% (1962)

67% (1969)

72% (1964)

65% (1961)

71% (1970)

72% (1969)

72% (1977)