pecking order vs progression

pecking order

noun
  • The natural hierarchy of social status and dominance occurring in a group of birds. 

  • The usually informal hierarchy of authority or command, often partial or approximate, as determined by the especially natural propensity for domination of different members of a specific group over each other, such as older brothers and sisters over their younger siblings. 

progression

noun
  • Development, increase, evolution. 

  • A sequence obtained by adding or multiplying each term by a constant. 

  • chord progression 

  • The act of moving from one thing to another. 

  • The act of moving forward or proceeding in a course; motion onward. 

  • The making an exercise more exerting by manipulating the details of its performance like loaded weight, range of motion, angle, speed. 

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