dementedness vs hydrophobia

dementedness

noun
  • The quality of being demented. 

hydrophobia

noun
  • A morbid fear of water; aquaphobia. 

  • An aversion to water, as a symptom of rabies; the disease of rabies itself. 

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