sustentation vs sustention

sustentation

noun
  • The act or the result of sustaining; sustainment. 

  • The aggregate of the functions by which a living organism is maintained in a normal condition of weight and growth. 

  • The scheme by which the ministers of the Free Church of Scotland are supported by voluntary contributions not local or congregational, but with a national altruism or solidarity paid into a great central fund, out of which equal stipends are paid to all alike. 

sustention

noun
  • sustentation 

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