intelligibility vs lucidity

intelligibility

noun
  • That which is intelligible; the degree to which something is intelligible. 

  • The quality of recorded speech of every word being understandable. 

lucidity

noun
  • The property of being lucid, lucidness. 

  • The state of being aware that one is dreaming, i.e. being in a lucid dream. 

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