creative work vs masterpiece

creative work

noun
  • A tangible manifestation of creative effort, such as literature, music, paintings, and software. 

masterpiece

noun
  • A work of outstanding creativity, skill or workmanship. 

  • A work created in order to qualify as a master craftsman and member of a guild. 

  • A piece of work that has been given much critical praise, especially one that is considered the greatest work of a person's career. 

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