expedient vs ghost writer

expedient

noun
  • A method or means for achieving a particular result, especially when direct or efficient; a resource. 

adj
  • Suitable to effect some desired end or the purpose intended. 

  • Governed by self-interest, often short-term self-interest. 

  • Affording short-term benefit, often at the expense of the long-term. 

ghost writer

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