auto racing vs championship

auto racing

noun
  • Any of various sports in which automobiles (motor cars) are raced, either around a track, on roads or across country 

championship

noun
  • A competition to determine a champion, especially the final of a series of competitions. 

  • The position of champion, or winner. 

  • Defense or support of some cause. 

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