dream up vs procreate

dream up

verb
  • To have an imaginative, unusual or foolish idea, to invent something unreal. 

procreate

verb
  • To originate, create or produce something. 

  • To beget or conceive (offspring). 

  • To reproduce. 

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