XXX vs filthy

XXX

adj
  • Extra strong; very high quality. 

  • Designating extreme or hardcore pornography. 

verb
  • To delete; to cross out, especially to conceal or suggest vulgar language. 

noun
  • Triple X syndrome. 

symbol
  • An indicator of hazard or poison. 

  • Traditional brewer's mark for barrels of extra strong beer—extended to other alcoholic beverages and other products having an extra strong dimension (varying from laundry soap to pornography). 

filthy

adj
  • Covered with filth; very dirty. 

  • Obscene or offensive. 

  • Very unpleasant or disagreeable. 

verb
  • To make very dirty; to saturate something with dirt. 

  • To cover in filth. 

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