dismal vs rare as hen's teeth

dismal

adj

  • Disappointingly inadequate. 

  • Causing despair; gloomy and bleak. 

  • Depressing, dreary, cheerless. 

  • Disastrous, calamitous 

rare as hen's teeth

adj

  • extremely uncommon 

How often have the words dismal and rare as hen's teeth occurred in a corpus of books? (source: Google Ngram Viewer )