old hat vs unconventional

old hat

adj
  • Very familiar; common, hackneyed or out of date. 

unconventional

noun
  • Something or someone that is unconventional. 

adj
  • Not adhering to convention or accepted standards 

  • Atypical 

  • Out of the ordinary 

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