captor vs preserver

captor

noun
  • One who is holding a captive or captives. 

  • One who catches or has caught or captured something or someone. 

preserver

noun
  • One who preserves. 

  • A person who prepares preserves of fruit or preserved meats. 

  • A person who refinishes furniture. 

  • A life preserver. 

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