downstairs vs storey

downstairs

noun
  • The lower floor of a house, at ground level; especially the servants’ quarters. 

  • The genitalia. 

adj
  • Located on a lower floor. 

adv
  • Down the stairs. 

  • In or to hell. 

  • Regarding the genitalia. 

storey

noun
  • A floor or level of a building or ship. 

  • A vertical level in certain letters, such as a and g. 

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