X-rated vs XXXX

X-rated

adj
  • Pornographic or indecent. 

  • Denoting a film given an X classification. 

XXXX

adj
  • X-rated, pornographic 

name
  • a fuck / damn. 

  • Tetrasomy X, a rare chromosomal disorder affecting females, caused by the presence of four X chromosomes instead of two present in the usual human karyotype. 

How often have the words X-rated and XXXX occurred in a corpus of books? (source: Google Ngram Viewer )