reenter vs retrocede

reenter

verb
  • To enter again; return into. 

  • To enter again; retype, reinput. 

  • To cut deeper where the aqua fortis has not bitten sufficiently. 

retrocede

verb
  • To go back. 

  • To grant back. 

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