longhouse vs petty-house

longhouse

noun
  • A long communal housing of the Iroquois and some other American Indians, the Malaysians, the Indonesians, the Vikings, and many other peoples. 

petty-house

noun
  • An outhouse: an outbuilding used as a lavatory. 

How often have the words longhouse and petty-house occurred in a corpus of books? (source: Google Ngram Viewer )