affliction vs formication

affliction

noun
  • Something which causes pain, suffering, distress or agony. 

  • A state of pain, suffering, distress or agony. 

formication

noun
  • An abnormal skin sensation similar to that of insects crawling over or within the skin; a tactile hallucination involving such a sensation. A common side-effect of substance abuse, it can also be experienced with high fever, menopause, skin cancer, diabetic neuropathy, or herpes zoster. 

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