forklift vs lift truck

forklift

noun
  • A small industrial vehicle with a power-operated fork-like pronged platform that can be raised and lowered for insertion under a load, often on pallets, to be lifted and moved. 

verb
  • To move or stack with, or as if with, such a vehicle. 

lift truck

noun
  • Synonym of forklift 

How often have the words forklift and lift truck occurred in a corpus of books? (source: Google Ngram Viewer )