feather one's nest vs pay off

feather one's nest

verb
  • To achieve benefits, especially financial ones, by taking advantage of the opportunities with which one is presented; to amass a comfortable amount of personal wealth. 

pay off

verb
  • To become worthwhile; to produce a net benefit. 

  • To bribe, especially to deter oversight. 

  • To pay back; to repay. 

  • To pay back (repay, pay off) the entirety of a loan, thereby effecting the release of a lien on. 

  • To fall to leeward, as the head of a vessel under sail. 

How often have the words feather one's nest and pay off occurred in a corpus of books? (source: Google Ngram Viewer )