garbage collector vs street sweeper

garbage collector

noun
  • A worker who removes refuse. 

  • An algorithm, procedure or thread dedicated to garbage collection: reclaiming resources which are no longer in use. 

street sweeper

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

  • A machine used to sweep streets. 

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