pull someone's bacon out of the fire vs pull someone's chestnuts out of the fire

pull someone's bacon out of the fire

verb
  • To rescue someone, especially at the last moment. 

pull someone's chestnuts out of the fire

verb
  • Synonym of pull someone's bacon out of the fire (“rescue someone, especially at the last moment”) 

  • To do another person's difficult work. 

How often have the words pull someone's bacon out of the fire and pull someone's chestnuts out of the fire occurred in a corpus of books? (source: Google Ngram Viewer )