trust territory vs trusteeship

trust territory

noun
  • a territory placed under the administration of a state by the United Nations 

trusteeship

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

  • Office or function of a trustee. 

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