enthrallment vs servitude

enthrallment

noun
  • The act of enthralling or the state of being enthralled 

servitude

noun
  • A qualified beneficial interest severed or fragmented from the ownership of an inferior property and attached to a superior property or to some person other than the owner; the most common form is an easement. 

  • The state of being a slave; slavery; being forced to work for others or do their bidding without one's consent or against one's will, either in perpetuity or for a period of time over which one has little or no control. 

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