SMS vs txt

SMS

verb
  • To send a message on a cell phone. 

noun
  • SMS — Seiner Majestät Schiff – literally, "His Majesty's Ship" in German; 

  • A ship prefix for a ship in the navy of the Empire of Germany (usually for the period leading to WWI and WWI) 

txt

verb
  • To text; to send a text message (to). 

noun
  • text, text message 

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