on the order of vs selfsame

on the order of

prep
  • In the manner of; along the lines of; like; of a similar kind to; more-or-less equivalent to. 

adv
  • Approximately. 

selfsame

adj
  • Chiefly preceded by the: precisely the same; the very same; the same not only in being similar but in being identical. 

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