A level vs bungholing

A level

noun
  • anal sex. 

  • A non-compulsory examination taken in the final two years in British high schools; the qualification obtained by passing such an exam 

bungholing

noun
  • anal sex 

  • ruining, screwing-over 

adj
  • buggering 

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