possess vs retain

possess

verb
  • To have control or possession of, but not to own (a chattel or an interest in land). 

  • To have (something) as, or as if as, an owner; to have, to own. 

  • To dominate sexually; to have sexual intercourse with. 

  • Of an idea, thought, etc.: to dominate (someone's mind); to strongly influence. 

  • Of a person: to control or dominate (oneself or someone, or one's own or someone's heart, mind, etc.). 

  • To inhabit or occupy a place. 

  • Of a supernatural entity, especially one regarded as evil: to take control of (an animal or person's body or mind). 

  • To dominate (a person) sexually; to have sexual intercourse with (a person). 

retain

verb
  • To keep in possession or use. 

  • To employ by paying a retainer. 

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

  • To keep in one's pay or service. 

  • To hold secure. 

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