hyperspace drive vs warp drive

hyperspace drive

noun
  • a hypothetical propulsion system for spacecraft that would "warp" spacetime 

warp drive

noun
  • a technological device that warps spacetime to enable movement through space in a non-Newtonian manner 

  • an engine that allows a vessel to travel faster-than-light by manipulating spacetime to bypass Einstein's restrictive light barrier 

How often have the words hyperspace drive and warp drive occurred in a corpus of books? (source: Google Ngram Viewer )