76% (1960)

62% (2007)

70% (2002)

46% (1950)

62% (1970)

60% (1974)

59% (1969)

68% (1963)

74% (1971)

50% (1963)

61% (1970)

20% (1973)

59% (1964)

72% (1962)

77% (1970)

90% (1961)

69% (1963)

61% (1969)

59% (1957)

62% (1968)