commit suicide vs strike down

commit suicide

verb
  • To kill oneself; to take one's own life. 

strike down

verb
  • To kill someone or something; to cause to die suddenly. 

  • To prostrate by illness. 

  • To knock down. 

  • To invalidate (a law, statute etc.) 

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