christening vs requiem

christening

noun
  • Any instance of someone's or something's being christened. 

  • The Christian sacrament at which someone, usually a child, is baptized and given a Christian name. 

requiem

noun
  • A large or dangerous shark, specifically, (zoology) a member of the family Carcharhinidae. 

  • A piece of music composed to honor a dead person. 

  • A mass (especially Catholic) to honor and remember a dead person. 

  • A musical composition for such a mass. 

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