need vs salvage

need

verb
  • To be required; to be necessary. 

  • To be obliged or required (to do something). 

  • To want strongly; to feel that one must have something. 

  • To have an absolute requirement for. 

noun
  • Lack of means of subsistence; poverty; indigence; destitution. 

  • A requirement for something; something needed. 

salvage

verb
  • to put to use. 

  • to rescue. 

  • To make new or restore for the use of being saved. 

  • To apprehend and execute (a suspected criminal) without trial. 

  • To perform summary execution. 

noun
  • The similar rescue of property liable to loss; the property so rescued. 

  • The money from the sale of rescued goods. 

  • Summary execution, extrajudicial killing. 

  • The rescue of a ship, its crew and passengers or its cargo from a hazardous situation. 

  • The ship, crew or cargo so rescued. 

  • The compensation paid to the rescuers. 

  • Anything put to good use that would otherwise have been wasted, such as damaged goods. 

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