diminish vs drain away

diminish

verb
  • To disappear gradually. 

  • To taper. 

  • To take away; to subtract. 

  • To make smaller. 

  • To lessen the authority or dignity of; to put down; to degrade; to abase; to weaken; to nerf (in gaming). 

  • To become less or smaller. 

drain away

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

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