downturn vs striction

downturn

noun
  • A downward trend, or the beginnings of one; a decline. 

verb
  • To decline 

  • To turn downwards 

striction

noun
  • The act of constricting, or the state of being constricted. 

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