artificial vs chemical-free

artificial

adj
  • Man-made; made by humans; of artifice. 

  • Insincere; fake, forced, or feigned. 

  • Conveying some meaning other than the actual contents of one's hand. 

  • Not natural or normal: imposed arbitrarily or without regard to the specifics or normal circumstances of a person, a situation, etc. 

chemical-free

adj
  • free of or produced without the addition or use of artificial chemicals. 

  • not involving the use of artificial chemicals in farming, such as insecticides or fertilisers. 

How often have the words artificial and chemical-free occurred in a corpus of books? (source: Google Ngram Viewer )