church service vs vespers

church service

noun
  • A formalized period of communal worship, often but not exclusively occurring on Sunday, or Saturday in the case of those churches practicing Sabbatarianism. 

  • A book containing the religious forms of such worship. 

vespers

noun
  • The sixth of the seven canonical hours, an evening prayer service 

How often have the words church service and vespers occurred in a corpus of books? (source: Google Ngram Viewer )