megalomania vs selfishness

megalomania

noun
  • An obsession with grandiose or extravagant things or actions. 

  • A psychopathological condition characterized by delusional fantasies of wealth, power, or omnipotence. 

selfishness

noun
  • the quality of being selfish; the condition of putting one's own interests before those of others. 

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