drain away vs dwindle

drain away

verb
  • To diminish over time; to disappear or leak out gradually. 

dwindle

verb
  • To fall away in quality; degenerate, sink. 

  • To decrease, shrink, diminish, reduce in size or intensity. 

  • To lessen; to bring low. 

  • To break up or disperse. 

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