supply teacher vs teaching

supply teacher

noun
  • A teacher who fills a temporary position in a school on a short-term basis; often supplied by an agency. 

teaching

noun
  • The profession of educating people; the activity that a teacher does when he/she teaches. 

  • Something taught by a religious or philosophical authority. 

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