force in vs impregnate

force in

verb
  • To make something larger fit in a smaller or tight place with brute force 

impregnate

verb
  • To fill pores or spaces with a substance. 

  • To saturate, or infuse. 

  • To fertilize. 

  • To cause to become pregnant. 

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