pep vs vitality

pep

noun
  • Energy, high spirits. 

verb
  • To inject with energy and enthusiasm. 

vitality

noun
  • Energy or vigour. 

  • The capacity to live and develop. 

  • That which distinguishes living from nonliving things; life, animateness. 

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