bookkeeping vs mopping

bookkeeping

noun
  • General tasks for maintaining a system. 

  • The skill or practice of keeping books or systematic records of financial transactions, e.g. income and expenses. 

mopping

noun
  • The process of cleaning with a mop. 

  • An application of molten asphalt to a roof etc. 

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