instability vs security

instability

noun
  • The quality of being unstable. 

  • A state that is not in equilibrium, or in which a small change has a large irreversible effect. 

security

noun
  • Proof of ownership of stocks, bonds or other investment instruments. 

  • Property etc. temporarily relinquished to guarantee repayment of a loan. 

  • Something that secures the fulfillment of an obligation or law. 

  • A guarantee. 

  • The condition of not being threatened, especially physically, psychologically, emotionally, or financially. 

  • Something that secures. 

  • An organization or department responsible for providing security by enforcing laws, rules, and regulations as well as maintaining order. 

  • Freedom from apprehension. 

  • A tradeable financial asset, such as a share of stock.ᵂ 

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