bombardment vs suicide bombing

bombardment

noun
  • the act of bombing, especially towns or cities 

  • heavy artillery fire 

  • the incidence of an intense stream of high-energy particles directed at a substance 

suicide bombing

noun
  • An attack carried out by a suicide bomber or a group of them. 

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