backset vs descent

backset

noun
  • A check; a relapse; a discouragement; a setback. 

  • Whatever is thrown back in its course, such as water. 

verb
  • To plow again in the fall; said of prairie land broken up in the spring. 

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 backset and descent occurred in a corpus of books? (source: Google Ngram Viewer )