SEAT vs merchant ship

SEAT

noun

  • An automobile from Sociedad Española de Automóviles de Turismo 

  • Single engine air tanker. 

name

  • Sociedad Española de Automóviles de Turismo, a Spanish automobile manufacturer. 

merchant ship

noun

  • A marine cargo vessel. 

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