combat engineer vs minesweeper

combat engineer

noun
  • A soldier employed to carry out engineering tasks in support of land forces during combat operations, facilitating the mobility of friendly forces while impeding that of the enemy; traditionally and often still today called a sapper. 

minesweeper

noun
  • A vehicle, device or person with the purpose of removing explosive mines (landmines or water mines). 

  • A logic-based computer game in which the player has to discover the position of mines in a rectangular grid, based on numerical hints. 

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