trying vs unchallenging

trying

noun
  • The act by which one tries something; an attempt. 

adj
  • Difficult to endure; arduous. 

  • Irritating, stressful or bothersome. 

unchallenging

adj
  • Not challenging; easy to do. 

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