effacement vs erasement

effacement

noun
  • The act of expunging, of wiping out; expungement. 

  • A shortening, or thinning, of the cervix before or during early labour. 

  • Withdrawal in order to make oneself inconspicuous; the making of oneself inconspicuous. 

erasement

noun
  • erasure; obliteration 

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