basement vs stairs

basement

noun
  • A floor of a building below ground level. 

  • Last place in a sports conference standings. 

  • A mass of igneous or metamorphic rock forming the foundation over which a platform of sedimentary rocks is laid. 

stairs

noun
  • A contiguous set of steps connecting two floors. 

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