subsistence vs sustainment

subsistence

noun
  • The act of maintaining oneself at a minimum level. 

  • Embodiment or personification or hypostasis of an underlying principle or quality. 

  • Real being; existence. 

  • Inherency. 

  • Something (food, water, money, etc.) that is required to stay alive. 

sustainment

noun
  • The act of sustaining something. 

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