inflatable vs lifeboat

inflatable

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

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

adj
  • Able to be inflated or blown up. 

lifeboat

noun
  • A boat especially designed for saving the lives of shipwrecked people or people in distress at sea (either launched from the shore with a crew, or else carried on board a larger ship). 

  • An emergency vehicle carried aboard a spaceship. 

verb
  • To rescue; to carry to safety 

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