attach too much importance to vs underestimate

attach too much importance to

underestimate

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

noun
  • An estimate that is too low. 

How often have the words attach too much importance to and underestimate occurred in a corpus of books? (source: Google Ngram Viewer )