errand vs thing to be done

errand

verb
  • To send someone on an errand. 

  • To go on an errand. 

noun
  • An oral message trusted to a person for delivery. 

  • A mundane mission of no great consequence, concerning household or business affairs (dropping items by, doing paperwork, going to a friend's house, etc.) 

  • The purpose of such a journey. 

thing to be done

How often have the words errand and thing to be done occurred in a corpus of books? (source: Google Ngram Viewer )