abstain vs cohabit

abstain

verb
  • Deliberately refrain from casting one's vote at a meeting where one is present. 

  • Refrain from (something or doing something); keep from doing, especially an indulgence. 

cohabit

verb
  • To live together with someone else, especially in a romantic and sexual relationship but without being married. 

  • To coexist in common environs with. 

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