generate vs spark off

generate

verb
  • To appear or occur; be generated. 

  • To produce as a result of a chemical or physical process. 

  • To procreate, beget. 

  • To form a figure from a curve or solid. 

  • To bring into being; give rise to. 

spark off

verb
  • To initiate something by providing the necessary conditions. 

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