audience vs listenership

audience

noun
  • A widespread or nationwide viewing or listening public, as of a TV or radio network or program. 

  • The readership of a book or other written publication. 

  • A following. 

  • An audiencia (judicial court of the Spanish empire), or the territory administered by it. 

  • A group of people within hearing; specifically, a large gathering of people listening to or watching a performance, speech, etc. 

  • A formal meeting with a state or religious dignitary. 

listenership

noun
  • The audience that listens to a certain form or genre of audio material (specifically (Internet, radio), an audio broadcast such as a radio program or a podcast). 

  • The act of paying attention to a conversation or speech; listening. 

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