deprecate vs underrate

deprecate

verb
  • To belittle or express disapproval of. 

  • To declare something obsolescent; to recommend against a function, technique, command, etc. that still works but has been replaced. 

underrate

verb
  • to underestimate; to make too low a rate or estimate 

noun
  • A price less than the value. 

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