deterioration vs progression

deterioration

noun
  • The process of making or growing worse, or the state of having grown worse. 

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 deterioration and progression occurred in a corpus of books? (source: Google Ngram Viewer )