expunge vs stamp out

expunge

verb
  • To eliminate completely; to annihilate. 

  • To delete permanently (e-mail etc.) that was previously marked for deletion but still stored. 

  • To erase or strike out. 

stamp out

verb
  • To get rid of totally; to eradicate. 

  • To extinguish by stamping. 

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