lean-to vs pigsty

lean-to

noun
  • A shelter with a sloped roof; also a building with a similar construction attached to the side of a building as an extension. 

pigsty

noun
  • An enclosure where pigs are kept. 

  • A dirty or very untidy place. 

How often have the words lean-to and pigsty occurred in a corpus of books? (source: Google Ngram Viewer )