double date vs festivity

double date

noun
  • A (romantic) date that two couples go on together. 

verb
  • To go on a double date. 

festivity

noun
  • A festival or similar celebration. 

  • An experience or expression of celebratory feeling, merriment, gaiety. 

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