dead calm vs quiescent

dead calm

adj

  • Completely still with no waves and no wind. 

noun

  • The condition of a perfectly flat sea with no waves and no wind. 

quiescent

adj

  • Not sounded; silent. 

  • Non-proliferating. 

  • Inactive, quiet, at rest. 

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