bettering vs constructive

bettering

noun
  • improvement 

constructive

adj
  • Relating to or causing construction. 

  • Not direct or expressed, but inferred. 

  • Imputed by law; created to give legal effect to something for equitable reasons, as with constructive notice or a constructive trust. 

  • Carefully considered and meant to be helpful. 

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