conjure up vs invoke

conjure up

verb
  • To generate (an image or an idea) in one's mind. 

  • To create or produce something, seemingly magically. 

  • To call up or command a spirit or devil by an incantation. 

invoke

verb
  • To call to mind (something) for some purpose. 

  • To appeal for validation to a (notably cited) authority. 

  • To cause (a program or subroutine) to execute. 

  • To solicit, petition for, appeal to a favorable attitude. 

  • To conjure up with incantations. 

  • To bring about as an inevitable consequence. 

  • To call upon (a person, a god) for help, assistance or guidance. 

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