eupnea vs inhalation

eupnea

noun
  • Normal, relaxed breathing; healthy condition of inhalation and exhalation. 

inhalation

noun
  • The substance (medicament) which is inhaled. 

  • The act of inhaling; inbreathing. 

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