hip-hop vs mutter

hip-hop

verb
  • To perform hip-hop music. 

  • To move by hopping or with a hopping motion. 

noun
  • An Afro-American urban youth culture based on rap music, breakdancing etc. 

  • A form of popular and dance music featuring strong percussion and a powerful rhythm, usually accompanied by rapping. 

mutter

verb
  • To make a sound with a low, rumbling noise. 

  • To speak softly and incoherently, or with imperfect articulations. 

  • To utter words, especially complaints or angry expressions, indistinctly or with a low voice and lips partly closed; to say under one's breath. 

noun
  • A repressed or obscure utterance; an instance of muttering. 

  • Peas. 

How often have the words hip-hop and mutter occurred in a corpus of books? (source: Google Ngram Viewer )