forward stroke vs oblique mark

forward stroke

noun
  • Synonym of forward slash. 

oblique mark

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

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