oesophagus vs trachea

oesophagus

noun
  • The tube that carries food from the pharynx to the stomach. 

trachea

noun
  • A thin-walled, cartilaginous tube connecting the larynx to the bronchi. 

  • One of the cuticle-lined primary tubes in the respiratory system of an insect, which extend throughout its body. 

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