abstention vs coitus interruptus

abstention

noun
  • The act of abstaining or refraining (from). 

  • Non-participation in the political world; as a country avoiding international affairs. 

  • The act of declining to vote on a particular issue. 

coitus interruptus

noun
  • Sexual intercourse interrupted by withdrawal of the penis before ejaculation. 

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