black coal vs bypass

black coal

noun
  • coal 

  • high-quality coal 

bypass

noun
  • A section of pipe that conducts a fluid around some other fixture. 

  • The act of going past or around. 

  • An electrical shunt. 

  • A road that passes around something, such as a residential area or business district. 

  • An alternative passage created to divert a bodily fluid around a damaged organ; the surgical procedure to construct such a bypass. 

verb
  • To avoid an obstacle etc, by constructing or using a bypass. 

  • To ignore the usual channels or procedures. 

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