cohabit vs procreate

cohabit

verb
  • To coexist in common environs with. 

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

procreate

verb
  • To originate, create or produce something. 

  • To beget or conceive (offspring). 

  • To reproduce. 

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