ring back vs welsh

ring back

verb
  • To return a phone call. 

  • To make another phone call to the same person. 

welsh

verb
  • To go back on one's word. 

  • To cheat or swindle someone, often by not paying a debt, especially a gambling debt. 

How often have the words ring back and welsh occurred in a corpus of books? (source: Google Ngram Viewer )