beset vs knock for a loop

beset

verb
  • To attack or assail, especially from all sides. 

  • Of a ship, to get trapped by ice. 

  • To surround or hem in. 

  • To decorate something with jewels etc. 

knock for a loop

verb
  • To astonish; to stagger or overwhelm; to confuse or disorient. 

How often have the words beset and knock for a loop occurred in a corpus of books? (source: Google Ngram Viewer )