homosexuality vs sexual orientation

homosexuality

noun
  • The state of being sexually attracted primarily or exclusively to persons of the same sex, sometimes (potentially offensive) restricted to same-sex attraction between males. 

  • Sexual activity with a person of the same sex, sometimes (potentially offensive) restricted to same-sex sex between males. 

sexual orientation

noun
  • One's tendencies of sexual attraction, considered as a whole. 

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