overstress vs understate

overstress

verb
  • To place excessive emphasis on something. 

  • To place excessive physical stress on something, especially to such an extent that it deforms or breaks. 

understate

verb
  • To state (something) with a lack of emphasis, in order to express irony. 

  • To state (something) with less completeness than needed; to minimise or downplay. 

  • To state a quantity that is too low. 

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