XXX vs obscene

XXX

adj
  • Extra strong; very high quality. 

  • Designating extreme or hardcore pornography. 

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). 

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

obscene

adj
  • Offensive to standards of decency or morality. 

  • Disgusting or repulsive. 

  • Lewd or lustful. 

  • Liable to corrupt or deprave. 

  • Beyond all reason; excessive. 

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