currycomb vs ostler

currycomb

noun
  • A comb or brush, having rubber or plastic teeth, used to groom horses. 

verb
  • To groom using such a comb. 

ostler

noun
  • A person employed at an inn, hostelry, or stable to look after horses; a groom 

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