carpet sweeper vs street sweeper

carpet sweeper

noun
  • A mechanical (not electric) device for cleaning carpets by means of a rotating brush. 

street sweeper

noun
  • A machine used to sweep streets. 

  • A person who is employed to sweep streets, pavements, and gutters, keeping them clear of litter. 

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