overestimate vs overstatement

overestimate

noun
  • An estimate that is too high. 

verb
  • To judge or calculate too highly. 

overstatement

noun
  • An exaggeration; a statement in excess of what is reasonable. 

  • The tendency to overstate. 

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