run of luck vs serendipity

run of luck

noun
  • A series of wins in gambling. 

serendipity

noun
  • A combination of events which have come together by chance to make a surprisingly good or wonderful outcome. 

  • An unsought, unintended, and/or unexpected, but fortunate, discovery and/or learning experience that happens by accident. 

  • The occurrence and development of events by chance in a happy or beneficial way. 

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