cumshaw vs perquisite

cumshaw

noun
  • A gratuity or tip as thanks for a service 

verb
  • To give or make a present to. 

perquisite

noun
  • A gratuity. 

  • Any monetary or other incidental benefit beyond salary. 

  • A privilege or possession held or claimed exclusively by a certain person, group or class. 

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