betterment vs diminution

betterment

noun
  • An improvement. 

  • An improvement to a property that adds to its value. 

diminution

noun
  • A lessening, decrease or reduction. 

  • a compositional technique where the composer shortens the melody by shortening its note values. 

  • The act or process of making diminutive. 

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