clarification vs escape route

clarification

noun
  • The act of freeing from obscurities. 

  • The act of clarifying; the act or process of making clear or transparent by freeing visible impurities; particularly, the clearing or fining of liquid substances from feculent matter by the separation of the insoluble particles which prevent the liquid from being transparent. 

escape route

noun
  • A way out of a difficult or unpleasant situation. 

  • A path used by someone to escape from a dangerous place. 

How often have the words clarification and escape route occurred in a corpus of books? (source: Google Ngram Viewer )