undocumented vs unofficial

undocumented

adj
  • Not having official documents that provide identification, authorization, etc. 

  • Lacking instructions or reference material. 

  • Not having official documentation required to legally enter, reside in, or work in a country. 

noun
  • Synonym of undocumented immigrant 

unofficial

adj
  • Not officially established. 

  • Not acting with official authority. 

  • Implicitly true but withheld and/or contradicted by authority. 

  • Not listed in a national pharmacopeia etc. 

How often have the words undocumented and unofficial occurred in a corpus of books? (source: Google Ngram Viewer )