grovel vs prostrate oneself

grovel

verb
  • To be prone on the ground. 

  • To be slavishly nice to someone or apologize in the hope of securing something. 

  • To take pleasure in mundane activities. 

  • To abase oneself before another person. 

  • To crawl. 

prostrate oneself

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