backslash vs drop-off

backslash

noun
  • |passage= […] I was trying to find a web-site for which I had been given the following address: http://www.isop.ucla.edu/pacrim/pubs/korjournal.htm. […] I began to work backwards, removing first the last part of the address following the last backslash (/korjournal.htm).}} 

  • The punctuation mark \. 

  • Used erroneously in reference to, or in reading out, the ordinary slash, that is, the punctuation mark /. 

verb
  • To escape (a metacharacter) by prepending a backslash that serves as an escape character, thereby forming an escape sequence. 

drop-off

noun
  • A visitor to a website who ceases to continue using and navigating around the site after reaching some specified page; or such an act of cessation. 

  • A sudden downward slope. 

  • A delivery; the act of leaving a package, etc. 

  • The precipitous outer side of a coral reef, facing the open sea. 

  • A sudden decrease. 

  • A space reserved outside a bus or railway station for vehicles stopping to drop off passengers for onward transit. 

  • A time during which passengers, such as school children, are dropped off. 

How often have the words backslash and drop-off occurred in a corpus of books? (source: Google Ngram Viewer )