arduity vs travail

arduity

noun
  • The state or quality of being arduous; steepness, difficulty. 

travail

noun
  • Arduous or painful exertion; excessive labor, suffering, hardship. 

  • Specifically, the labor of childbirth. 

verb
  • To toil. 

  • To go through the labor of childbirth. 

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