kindness vs solicitude

kindness

noun
  • An instance of kind or charitable behaviour. 

  • The state of being kind. 

solicitude

noun
  • The state of being solicitous; uneasiness of mind occasioned by fear of evil or desire for good; anxiety. 

  • Special or pronounced concern or attention. 

  • A cause of anxiety or concern. 

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