ignite vs start burning

ignite

verb
  • to commence burning. 

  • to spark off (something), to trigger 

  • to set fire to (something), to light (something) 

  • To subject to the action of intense heat; to heat strongly; often said of incombustible or infusible substances. 

start burning

How often have the words ignite and start burning occurred in a corpus of books? (source: Google Ngram Viewer )