hand off vs offload

hand off

verb
  • to pass (the ball) to a teammate 

  • to pass or transfer. 

offload

verb
  • to pass the ball. 

  • to deny a person on a standby list due to lack of space. 

  • to unload. 

  • to get rid of things, work, or problems by passing them on to someone or something else. 

  • to change a passengers' ticket status from "checked in" to "open", allowing further changes. (This applies regardless of whether the passenger has boarded the aircraft or not). 

noun
  • The act of offloading something, or diverting it elsewhere. 

  • The act of passing the ball to a team mate when tackled. 

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