perspicuousness vs salience

perspicuousness

noun
  • The state or characteristic of being perspicuous; perspicuity. 

salience

noun
  • A highlight; perceptual prominence, or likelihood of being noticed. 

  • Relative importance based on context. 

  • The condition of being salient. 

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