pinafore vs pinny

pinafore

noun
  • A sleeveless dress, often similar to an apron, generally worn over other clothes, and most often worn by young girls as an overdress. 

pinny

noun
  • A sleeveless dress, often similar to an apron, generally worn over other clothes. 

  • A colourful polyester or plastic vest worn over one's clothes, usually to mark one's team during group activities. 

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