unsustainable vs unwarranted

unsustainable

adj
  • Not sustainable. 

unwarranted

adj
  • Unjustified, inappropriate or undeserved. 

  • Not warranted; being without warrant, authority, or guaranty; unwarrantable. 

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