occupier vs sitting tenant

occupier

noun
  • One who occupies, particularly with respect to a foreign government controlling the territory of another. 

sitting tenant

noun
  • A tenant who is already in occupation of a premises, especially when there is a change of owner. The tenant is not evicted when the property is sold to a new owner. 

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