traveling vs travelling

traveling

adj
  • That travels (with one). 

noun
  • A violation committed by progressing while holding the ball instead of dribbling it. 

  • The action of the verb travel. 

travelling

adj
  • That travels (with one) 

noun
  • The act of one who travels; a journey. 

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