bygone vs sometime

bygone

adj
  • Having been or happened in the distant past. 

noun
  • An event that happened in the past. 

sometime

adj
  • Former, erstwhile; at some previous time. 

  • Occasional. 

adv
  • At an indefinite but stated time in the past or future. 

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