bollock vs scrotum

bollock

noun
  • A testicle. 

verb
  • To reprimand severely and grossly. 

  • To exhaust, tire out. 

scrotum

noun
  • The sac of skin and muscle that contains the testicles in most mammals. 

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