drain away vs regress

drain away

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

regress

verb
  • To move backwards to an earlier stage; to devolve. 

  • To move from east to west. 

  • To perform a regression on an explanatory variable. 

  • To interrogate a person in a state of trance about forgotten elements of their past. 

noun
  • The act of passing back; passage back; return; retrogression. 

  • In property law, the right of a person (such as a lessee) to return to a property. 

  • The power or liberty of passing back. 

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