sparring vs strife

sparring

noun
  • The act of one who spars. 

strife

noun
  • Striving; earnest endeavor; hard work. 

  • A trouble of any kind. 

  • Bitter conflict, sometimes violent. 

  • Exertion or contention for superiority, either by physical or intellectual means. 

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