holiday season vs national holiday

holiday season

noun
  • A period in the summer when people go on holiday (vacation). 

  • The period of the late fall and early winter when several holidays occur, such as Halloween, American Thanksgiving, Christmas, New Year's Day, Hanukkah, and Kwanzaa 

national holiday

noun
  • A public holiday. 

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

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