disimprovement vs impairment

disimprovement

noun
  • Reduction from a better to a worse state. 

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

impairment

noun
  • A downward revaluation, a write-down. 

  • A deterioration or weakening 

  • The result of being impaired 

  • A disability or handicap 

  • an inefficient part or factor. 

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