oblique mark vs shilling mark

oblique mark

noun
  • Synonym of slash ⟨/⟩, sometimes (generally proscribed) inclusive of similar marks such as the backslash ⟨\⟩. 

shilling mark

noun
  • Synonym of slash ⟨/⟩ in its use to mark the amount of shillings in a sum or (obsolete) in all its uses. 

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