citizenship vs ethnic group

citizenship

noun
  • The status of being a citizen, in its various senses. 

  • The state of being a citizen, in its various senses. 

ethnic group

noun
  • A group of people who identify with one another, especially on the basis of ancestral, national, cultural, historical or religious grounds. 

How often have the words citizenship and ethnic group occurred in a corpus of books? (source: Google Ngram Viewer )