contribution vs subscription

contribution

noun
  • The act of contributing. 

  • An amount of money given toward something. 

  • Something given or offered that adds to a larger whole. 

  • The taking part, often with the idea that it has led to (scientific etc.) progress. 

subscription

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

  • The signing of one's name. 

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

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

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