dissipate vs pile up

dissipate

verb
  • To drive away, disperse. 

  • To use up or waste; squander. 

  • To vanish by dispersion. 

  • To cause energy to be lost through its conversion to heat. 

pile up

verb
  • To form a pile, stack, or heap. 

  • To collect or accumulate, as a backlog. 

How often have the words dissipate and pile up occurred in a corpus of books? (source: Google Ngram Viewer )