libero vs vacuum cleaner

libero

noun
  • a sweeper 

  • a designated back-row player intended to be used as a ball-control specialist 

vacuum cleaner

noun
  • A domestic or industrial mobile machine for cleaning floors and similar surfaces that draws dust and other particles into a container (a cyclonic type bin, or a filter bag) by the suction created by an electric motor driving a fan. 

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