evaporate vs taper off

evaporate

verb
  • to give vent to; to dissipate 

  • to expel moisture from (usually by means of artificial heat), leaving the solid portion 

  • to transition from a liquid state into a gaseous state 

  • to disappear; to escape or pass off without effect 

taper off

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

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