downturn vs stagnation

downturn

noun

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

verb

  • To decline 

  • To turn downwards 

stagnation

noun

  • The state of being stagnant, without circulation. 

  • Inactivity. 

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