hoover vs libero

hoover

noun
  • A vacuum cleaner, irrespective of brand. 

verb
  • To clean (a room, etc.) with a vacuum cleaner, irrespective of brand. 

  • To use a vacuum cleaner, irrespective of brand. 

  • To suck in or inhale, as if by a vacuum cleaner. 

libero

noun
  • a sweeper 

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

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