lacking vs prepatent

lacking

noun
  • The absence of something; a lack. 

adj
  • Missing or not having enough of (a good quality, etc). 

prepatent

adj
  • Prior to the existence of a legal patent. 

  • Before symptoms (especially of infection) become manifest. 

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