fighting chance vs toss-up

fighting chance

noun
  • A chance that is dependent on success in a struggle, with the implication that such success is not unattainable. 

toss-up

noun
  • A decision in which neither choice is clearly favorable or unfavorable, or for which the outcome does not matter. 

  • Either of two outcomes that are equally likely. 

  • The toss of a coin used to decide some issue. 

How often have the words fighting chance and toss-up occurred in a corpus of books? (source: Google Ngram Viewer )