apathy vs enervation

apathy

noun
  • Lack of emotion or motivation; lack of interest or enthusiasm towards something; disinterest (in something). 

enervation

noun
  • State of being enervated; debility. 

  • Act of enervating; debilitation. 

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