national anthem vs serenade

national anthem

noun
  • The official song of a constituent state of a country. 

  • The official song of a nation or sovereign state, generally of a patriotic nature and played at events to celebrate or honor said state. 

serenade

noun
  • An instrumental composition in several movements. 

  • A love song that is sung directly to one's love interest, especially one performed below the window of a loved one in the evening. 

verb
  • To sing or play a serenade for (someone). 

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