intertwine vs untwine

intertwine

verb
  • To twine something together. 

  • To become twined together; to become mutually involved. 

untwine

verb
  • To free (one thing that is entwined with another), disentangle, extricate. 

  • To become untwisted or disentangled. 

  • To untwist the strands of (something entwined). 

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