half-crown vs shilling sign

half-crown

noun
  • A pre-decimal coin used in Britain, Ireland and New Zealand, equivalent to 30 pence or two shillings and six pence. 

shilling sign

noun
  • The symbol '/' used in the United Kingdom before decimalisation to separate shillings from pence when writing out sums of money. (Examples: 7/6 = seven shillings and six pence; 7/- = seven shillings exactly.) 

How often have the words half-crown and shilling sign occurred in a corpus of books? (source: Google Ngram Viewer )