agitate vs key up

agitate

verb
  • To disturb or excite; to perturb or stir up (a person). 

  • To cause to move with a violent, irregular action; to shake. 

key up

verb
  • To raise the intensity, excitement, tension, etc., of. 

  • To produce nervous tension in. 

  • To raise the pitch of. 

  • To raise (the whole ring of an arch) off its centering, by driving in the keystone forcibly. 

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