perself vs yourself

perself

pron
  • Per, themself; gender-neutral object of a verb or preposition that also appears as the subject, the reflexive form of per. 

yourself

pron
  • You (singular); used emphatically, especially to indicate exclusiveness of the referent's participation in the predicate, i.e., that no one else is involved. 

  • Your own self (singular). 

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