72% (1995)

76% (1976)

76% (1973)

73% (2002)

63% (1981)

78% (1983)

69% (1973)

65% (1967)

60% (1970)

68% (1966)

58% (1982)

60% (1995)

55% (1977)

64% (1979)

58% (1972)

61% (1974)

67% (1977)

67% (1998)

61% (1969)

59% (2007)