pier vs quay

pier

noun
  • A raised platform built from the shore out over water, supported on piles; used to secure, or provide access to shipping; a jetty. 

  • A structure supporting the junction between two spans of a bridge. 

  • A similar structure, especially at a seaside resort, used to provide entertainment. 

  • A rectangular pillar, or similar structure, that supports an arch, wall or roof, or the hinges of a gate. 

quay

noun
  • A stone or concrete structure on navigable water used for loading and unloading vessels; a wharf. 

verb
  • To land or tie up at a quay or similar structure, especially used in the phrase "quay up". 

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