indistinguishable vs to the same degree

indistinguishable

adj

  • Not capable of being perceived or known. 

  • Not distinguishable; not capable of being perceived, known, or discriminated as separate and distinct 

noun

  • Any of a set of things that cannot be distinguished. 

to the same degree

How often have the words indistinguishable and to the same degree occurred in a corpus of books? (source: Google Ngram Viewer )