bastardize vs mongrelize

bastardize

verb
  • To beget out of wedlock. 

  • To claim or demonstrate that someone is a bastard, or illegitimate. 

  • To reduce from a higher to a lower state, such as by removing refined elements or introducing debased elements; to debase. 

mongrelize

verb
  • To cross-breed 

  • To breed a mongrel 

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