sign over vs vouchsafe

sign over

verb
  • To transfer (property or rights) to somebody else by signing a document. 

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 sign over and vouchsafe occurred in a corpus of books? (source: Google Ngram Viewer )