homosexuality vs transsexuality

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. 

transsexuality

noun
  • The state, condition, or properties of being transsexual. 

  • The psychological diagnosis of gender identity disorder. 

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