rekindle vs spark up

rekindle

verb
  • To revive. 

  • To be kindled or ignited again. 

  • To kindle again. 

spark up

verb
  • to rekindle 

  • To provide electrification. 

  • To initiate (a conversation, debate etc.) 

  • to make more exotic or fun 

  • To light up; light a cigarette or start smoking a pipe, bong, etc. 

How often have the words rekindle and spark up occurred in a corpus of books? (source: Google Ngram Viewer )