bisexuality vs lesbianism

bisexuality

noun
  • The state of being sexually or romantically attracted to members of either sex or gender. 

  • The state of being bisexual (“having both male and female parts or roles”). 

lesbianism

noun
  • Female homosexuality; the state (of a woman) of being sexually attracted to other women. 

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