piazza vs portico

piazza

noun
  • A roofed gallery or arcade (for example around a public square or in front of a building). 

  • A public square, especially in Italian cities. 

portico

noun
  • A porch, or a small space with a roof supported by columns, serving as the entrance to a building. 

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