euphonious vs mellifluous

euphonious

adj
  • Of sounds, especially speech: demonstrating or possessing euphony; agreeable to the ear; pleasant-sounding. 

mellifluous

adj
  • Sweet, smooth and musical; pleasant to hear (generally used of a person's voice, tone or writing style). 

  • Flowing like honey. 

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