fault-finder vs grouser

fault-finder

grouser

noun
  • A temporary pile driven into the bottom of a river to hold a boat in position; a spud. 

  • A protrusion on the surface of a wheel or continuous track segment, intended to increase traction in soil, snow, or other loose material. 

  • A person who grouses; a grumbler. 

How often have the words fault-finder and grouser occurred in a corpus of books? (source: Google Ngram Viewer )