crewman vs roustabout

crewman

noun
  • Synonym of armoured crewman 

  • A member of a crew, especially the crew of a ship. 

roustabout

noun
  • an unskilled laborer, especially at an oilfield, at a circus or on a ship, 19th c. 

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