naughty vs soft-core

naughty

adj
  • Mischievous; tending to misbehave or act badly (especially of a child). 

  • Sexually provocative; now in weakened sense, risqué, cheeky. 

verb
  • To perform sexual acts upon. 

soft-core

How often have the words naughty and soft-core occurred in a corpus of books? (source: Google Ngram Viewer )