mark down vs undervalue

mark down

verb
  • To subtract marks or points from, for an error. 

  • To write a memorandum about. 

  • To reduce the price of. 

  • To draw a conclusion about something; to consider something to be a certain way. (Typically used with as.) 

  • To write down. 

undervalue

verb
  • To underestimate, or assign too low a value to. 

  • To have too little regard for. 

noun
  • An undervaluation; a price or rate below the actual worth. 

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