feather one's nest vs fructify

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. 

fructify

verb
  • To make productive or fruitful. 

  • To bear fruit; to generate useful products or ideas. 

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