delete vs retain

delete

verb
  • To defeat or dominate. 

  • To kill or murder. 

  • To remove, get rid of or erase, especially written or printed material, or data on a computer or other device. 

noun
  • A remainder of a music or video release. 

  • The delete character (U+007F or %7F). 

  • A deletion. 

retain

verb
  • To hold back (a pupil) instead of allowing them to advance to the next class or year. 

  • To employ by paying a retainer. 

  • To keep in one's pay or service. 

  • To keep in possession or use. 

  • To hold secure. 

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