heterosexuality vs straightness

heterosexuality

noun
  • The state of being sexually and romantically attracted primarily or exclusively to persons of the opposite sex. 

  • Sexual activity with a person of the opposite sex. 

straightness

noun
  • The state or quality of being straight (especially in the sense of "heterosexual"). 

  • The result or product of being straight. 

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