anguish vs undergo

anguish

verb
  • To suffer pain. 

  • To cause to suffer pain. 

noun
  • Extreme pain, either of body or mind; excruciating distress. 

undergo

verb
  • To suffer or endure; bear with. 

  • To experience; to pass through a phase. 

  • The project is undergoing great changes. 

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