blood, sweat and tears vs perspiration

blood, sweat and tears

noun

  • A person's determination and hard work. 

perspiration

noun

  • Hard work. 

  • The action or process of perspiring. 

  • A saline fluid secreted by the sweat glands; sweat. 

How often have the words blood, sweat and tears and perspiration occurred in a corpus of books? (source: Google Ngram Viewer )