assistance vs chagrin

assistance

noun
  • Aid; help; the act or result of assisting. 

chagrin

verb
  • To bother or vex; to mortify. 

noun
  • Distress of mind caused by a failure of aims or plans, want of appreciation, mistakes etc; vexation or mortification. 

  • A type of leather or skin with a rough surface. 

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