Essence vs Raven

Essence

name

  • A female given name of African-American usage. 

Raven

name

  • A female given name from English for a girl with raven hair, used since the 1970s. 

  • A male given name 

  • A surname. 

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