spring for vs vouchsafe

spring for

verb
  • To pay for; to offer money. 

vouchsafe

verb
  • To graciously give, to condescendingly grant a right, benefit, outcome, etc.; to deign to acknowledge. 

  • To receive or accept in condescension. 

  • To disclose or divulge. 

How often have the words spring for and vouchsafe occurred in a corpus of books? (source: Google Ngram Viewer )