holidays vs national holiday

holidays

noun
  • The season around Christmas, Hanukkah, and New Year's Day. 

  • (usually after possessive) holiday, vacation; time off work, especially if spent travelling away from home 

national holiday

noun
  • A public holiday. 

  • A statutory holiday enacted by a country to commemorate the country itself. 

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