countersignature vs subscription

countersignature

noun
  • A signature made to confirm or endorse another. 

subscription

noun
  • The formal acceptance of something, especially when verified with a signature. 

  • The signing of one's name. 

  • Access to a resource for a period of time, generally for payment. 

  • Contributing or promising to contribute money to a common fund. 

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