encroachment vs preservation

encroachment

noun
  • That which is gained by such unlawful intrusion. 

  • An intrusion upon another's possessions or rights; infringement. 

  • An unlawful diminution of the possessions of another. 

  • An entry into a place or area that was previously uncommon; an advance beyond former borders; intrusion; incursion. 

preservation

noun
  • The act of preserving; care to preserve; act of keeping from destruction, decay or any ill. 

  • The state of being preserved, how something has survived. 

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