chirography vs sig

chirography

noun
  • Synonym of autograph, writing in one's own hand. 

  • Synonym of handwriting or penmanship, one's personal skill at writing. 

  • Synonym of calligraphy, the art of beautiful writing. 

  • Synonym of palmistry, fortune-telling based on one's hand. 

sig

noun
  • A signature, especially on emails or newsgroup postings. 

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