posterior vs tail end

posterior

noun
  • The hinder parts of the body. 

  • The probability that a hypothesis is true (calculated by Bayes' theorem). 

adj
  • Following in order or in time. 

  • Next to, or facing the main stem or axis. 

  • Relating to or denoting presentation of a fetus in which the rear or caudal end is nearest the cervix and emerges first at birth. 

tail end

noun
  • The hindmost part of anything (a person, animal, or object), the rear end; the butt, buttocks; hindquarters, rump. 

  • The last part of a period of time, event, or situation; the concluding or final part. 

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