forget vs start the ball rolling

forget

verb
  • To lose remembrance of. 

  • To unintentionally not do, neglect. 

  • To unintentionally leave something behind. 

  • To cease remembering. 

  • Euphemism for fuck, screw (a mild oath). 

start the ball rolling

verb
  • Synonym of get the ball rolling. 

How often have the words forget and start the ball rolling occurred in a corpus of books? (source: Google Ngram Viewer )