notability vs unknown

notability

noun
  • The quality or state of being notable or eminent. 

  • A notable or eminent person or thing. 

  • Locally eminent people; the bourgeoisie or upper middle class 

unknown

adj
  • Not known; unidentified; not well known. 

noun
  • A variable (usually x, y or z) whose value is to be found. 

  • A person of no identity; a nonentity 

  • Any thing, place, or situation about which nothing is known; an unknown fact or piece of information. 

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