sponsorship vs trusteeship

sponsorship

noun
  • The state or practice of being a sponsor. 

  • The aid or support provided by a sponsor; backing or patronage. 

trusteeship

noun
  • Office or function of a trustee. 

  • The administrative control of a territory granted to a country by the Trusteeship Council of the United Nations. 

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