aptness vs recommendability

aptness

noun
  • suitability; the quality of being apt or suitable 

  • disposition of the mind; propensity 

  • speed or readiness in learning; docility 

  • proneness; tendency 

recommendability

noun
  • The quality of being recommendable. 

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