go downhill vs go to seed

go downhill

verb
  • To worsen or degenerate. 

go to seed

verb
  • To deteriorate; to decline into an unkempt or debased condition. 

  • To pass from flowering or ripening to the formation of seeds. 

How often have the words go downhill and go to seed occurred in a corpus of books? (source: Google Ngram Viewer )