expropriation vs sequestration

expropriation

noun
  • The act of expropriating; the surrender of a claim to private property; the act of depriving of private propriety rights. 

sequestration

noun
  • The process or act of sequestering; a putting aside or separating. 

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