falsify vs fill in

falsify

verb
  • To counterfeit; to forge. 

  • To misrepresent. 

  • To alter so as to make false; to make incorrect. 

  • To prove to be false. 

  • To show (an item of charge inserted in an account) to be wrong. 

fill in

verb
  • To fill; to replace material that is absent or has been removed. 

  • To substitute for somebody or something. 

  • To complete a form or questionnaire with requested information. 

  • To beat up; to physically assault. 

  • To inform somebody, especially to supply someone missing or missed information. 

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