dehydration vs rainlessness

dehydration

noun
  • The condition in which water in the body drops below normal levels, usually caused by illness, sweating or by not drinking enough. 

  • The act or process of removing water from something. 

rainlessness

noun
  • The state or condition of being rainless; lack of rain; drought 

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