altruism vs egoism

altruism

noun
  • Action or behaviour that benefits another or others at some cost to the performer. 

  • Regard for others, both natural and moral without regard for oneself; devotion to the interests of others; brotherly kindness. 

egoism

noun
  • Egotism (tendency to talk excessively about oneself). 

  • The tendency to think selfishly with exclusive self-interest in mind. 

  • The belief that moral behavior should be directed toward one's self-interest only. 

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