flak vs slating

flak

noun
  • Adverse criticism. 

  • A public-relations spokesperson. 

  • Anti-aircraft shell fire. 

  • Ground-based anti-aircraft guns firing explosive shells. 

slating

noun
  • A harsh criticism. 

  • Material for slating. 

  • Slates collectively. 

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