contemplate vs stew over

contemplate

verb
  • To look at on all sides or in all its aspects; to view or consider with continued attention; to regard with deliberate care; to meditate on; to study, ponder, or consider. 

  • To consider as a possibility. 

stew over

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