free lunch vs sop

free lunch

noun
  • Something obtained without any payment, obligation or effort. 

sop

noun
  • Something given or done to pacify or bribe. 

  • Something entirely soaked. 

  • A piece of turf placed in the road as a target for a throw in road bowling. 

  • A piece of solid food to be soaked in liquid food. 

  • Gravy. 

  • A weak, easily frightened or ineffectual person; a milksop 

verb
  • To soak in, or be soaked; to percolate. 

  • To steep or dip in any liquid. 

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