plod vs twelve

plod

noun
  • the police, police officers 

  • A slow or labored walk or other motion or activity. 

  • a police officer, especially a low-ranking one. 

verb
  • To walk or move slowly and heavily or laboriously (+ on, through, over). 

  • To toil; to drudge; especially, to study laboriously and patiently. 

  • To trudge over or through. 

twelve

noun
  • The police; law enforcement, especially a narcotics officer. 

  • A jury (normally composed of twelve persons). 

  • A twelve-bore gun. 

  • Front (front side of something, position in front of something). 

  • A group of twelve items. 

num
  • The cardinal number occurring after eleven and before thirteen, represented in Arabic numerals as 12 and in Roman numerals as XII. 

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