Jehovah's Witness vs Jehovian

Jehovah's Witness

noun

  • A member of the Christian church Jehovah's Witnesses. 

Jehovian

noun

  • A Jehovah's Witness. 

adj

  • Of or relating to Jehovah. 

How often have the words Jehovah's Witness and Jehovian occurred in a corpus of books? (source: Google Ngram Viewer )