introspection vs self-examination

introspection

noun
  • A looking inward; specifically, the act or process of self-examination, or inspection of one's own thoughts and feelings; the cognition which the mind has of its own acts and states 

self-examination

noun
  • An examination of oneself; scrutiny of one's own state, condition, motives, etc. 

  • The action of examining one's own body for signs of illness 

How often have the words introspection and self-examination occurred in a corpus of books? (source: Google Ngram Viewer )