drafting vs improvisation

drafting

noun
  • The act or process of producing a technical drawing, or draft. 

  • A method of preparing fibers for weaving. 

  • The practice among ground vehicle drivers or cyclists of following in a close line to reduce wind resistance. 

  • A profession, usually related to making technical drawings for architecture, engineering, or manufacturing. 

improvisation

noun
  • The act or art of composing and making music, poetry, and the like, extemporaneously 

  • That which is improvised; an impromptu. 

  • Musical technique, characteristic of blues music. 

  • The act of improvising, acting or going about something without planning ahead 

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