Trends in public knowledge about health and illness.
D000328:Adult; D000367:Age Factors; D000368:Aged; D003142:Communication; D004522:Educational Status; D005260:Female; D006266:Health Education; D006801:Humans; D007182:Income; D008297:Male; D008875:Middle Aged; D009790:Occupations; D012737:Sex Factors; D014481:United States