dearth vs drought

dearth

noun
  • A period or condition when food is rare and hence expensive; famine. 

  • Scarcity; a lack or short supply. 

drought

noun
  • A period of unusually low rainfall, longer and more severe than a dry spell. 

  • A longer than expected term without success, particularly in sport. 

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