catch fire vs firebomb

catch fire

verb
  • To become engulfed in flames, to combust. 

  • To become very popular or widespread; to take off. 

  • To be inspired by passion or zeal. 

firebomb

verb
  • To attack with a firebomb. 

noun
  • A weapon that causes fire; an incendiary weapon. 

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