sloth vs tiredness

sloth

noun
  • Laziness; slowness in the mindset; disinclination to action or labour. 

  • A herbivorous, arboreal South American mammal of the families Megalonychidae and Bradypodidae, noted for its slowness and inactivity. 

  • A collective term for a group of bears. 

tiredness

noun
  • The state of being tired. 

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