declass vs move down

declass

verb
  • To lower the class or social standing of. 

  • To remove from a class. 

move down

verb
  • to be demoted 

  • Used other than figuratively or idiomatically: see move, down. 

  • To demote 

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