disimprovement vs downturn

disimprovement

noun
  • Reduction from a better to a worse state. 

  • attempt to make something better while ending up worse than before. 

downturn

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

verb
  • To decline 

  • To turn downwards 

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