in contention vs taxing

in contention

prep
  • Used other than figuratively or idiomatically: see in, contention. 

  • Contending for a title or championship. 

taxing

noun
  • The act of imposing a tax. 

adj
  • Burdensome, difficult. 

  • With respect to an experience: exhausting; draining. 

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