obstacle vs perfection

obstacle

noun
  • Something that impedes, stands in the way of, or holds up progress, either physically or figuratively 

perfection

noun
  • A quality, endowment, or acquirement completely excellent; an ideal; faultlessness; especially, the divine attribute of complete excellence. 

  • The quality or state of being perfect or complete, so that nothing substandard remains; the highest attainable state or degree of excellence 

verb
  • To perfect. 

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