oblique mark vs strikethrough

oblique mark

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

strikethrough

noun
  • A horizontal or oblique line striking out individual characters. 

  • An overlaid horizontal line striking out other characters. 

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