drop in the sea vs farthing

drop in the sea

noun
  • A very small or insignificant amount; something of little importance. 

farthing

noun
  • A very small quantity or value; the least possible amount. 

  • Former British unit of currency worth one-quarter of an old penny; or a coin representing this. 

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