abend vs fall down on

abend

verb
  • To terminate abnormally. 

noun
  • The abnormal termination of a program. 

  • Termination of a process prior to completion. 

fall down on

verb
  • To fail at or leave incomplete. 

  • To stumble or unintentionally descend and land on 

  • To collapse so that the remains are on top of. 

  • To prostrate oneself in a position that rests on 

How often have the words abend and fall down on occurred in a corpus of books? (source: Google Ngram Viewer )