amelioration vs descent

amelioration

noun
  • An improvement. 

  • The act of making better. 

  • The process by which a term gains a more positive connotation over time. 

  • An ameliorative change of a concept or a repertoire of concepts. 

descent

noun
  • A drop to a lower status or condition; decline. 

  • A particular extension of the idea of gluing. 

  • A falling upon or invasion. 

  • A sloping passage or incline. 

  • Lineage or hereditary derivation. 

  • An instance of descending; act of coming down. 

  • A way down. 

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