appreciate vs underestimate

appreciate

verb
  • To be grateful or thankful for. 

  • To increase in value. 

  • To view as valuable. 

  • To be fully conscious of; understand; be aware of; detect. 

underestimate

noun
  • An estimate that is too low. 

verb
  • To perceive (someone or something) as having a lower value, quantity, worth, etc., than what he/she/it actually has. 

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