inflatable vs pneumatic

inflatable

adj
  • Able to be inflated or blown up. 

noun
  • Any other structure, artwork etc. that is inflated. 

  • A boat or dinghy that may be inflated when needed. 

pneumatic

adj
  • Powered by, or filled with, compressed air 

  • Of, relating to, or resembling air or other gases 

  • well-rounded; full-breasted; bouncy 

  • Of or relating to pneumatics 

  • Spiritual; of or relating to the pneuma 

  • Having cavities filled with air 

noun
  • In the gnostic theologian Valentinus' triadic grouping of man, the highest type; a person focused on spiritual reality (the other two being hylic and psychic). 

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