answerphone vs voicemail

answerphone

noun
  • A telephone containing a built-in device for recording incoming callers’ messages for later retrieval. 

voicemail

noun
  • A computerized interactive system for storing, processing and reproducing verbal messages left through a conventional telephone network. 

  • An individual message on such a system. 

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