assistance vs fosterage

assistance

noun
  • Aid; help; the act or result of assisting. 

fosterage

noun
  • The act of caring for another human being or animal. 

  • The act of fostering another's child as if it were one's own. 

  • The act of promoting or encouraging something. 

  • The condition of being the foster child. 

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