Echo vs Mania

Echo

name
  • An oread, punished by Hera by losing her own voice and only being able to mimic that of others. 

  • 60 Echo, a main belt asteroid. 

Mania

name
  • The goddess of the dead and ghosts. 

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