severity vs sufferance

severity

noun
  • The degree of something undesirable; badness or seriousness. 

  • The state of being severe. 

sufferance

noun
  • Acquiescence or tacit compliance with some circumstance, behavior, or instruction. 

  • A permission granted by the customs authorities for the shipment of goods. 

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