evening prayer vs vespers

evening prayer

noun
  • The second of the two services of the Daily Office, combining the canonical hours of vespers and compline. Commonly called evensong, especially when the service is musical. 

  • isha 

vespers

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

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