Kev vs prole

Kev

noun

  • A working-class male. 

name

  • A diminutive of the male given name Kevin. 

prole

noun

  • A pleb (ordinary person). 

  • A member of the proletariat; a proletarian. 

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