subside vs taper off

subside

verb
  • To fall downward; to become lower; to descend; to sink. 

  • To cease talking. 

  • To sink or fall to the bottom; to settle, as lees. 

  • To fall into a state of calm; to be calm again; to settle down; to become tranquil; to abate. 

taper off

verb
  • To diminish or lessen gradually; to become smaller, slower, quieter, etc. 

How often have the words subside and taper off occurred in a corpus of books? (source: Google Ngram Viewer )