logotype vs registered trademark

logotype

noun
  • A symbol or emblem that acts as a trademark or a means of identification of an institution or other entity, usually referred to as a logo. 

  • A single type combining two or more letters (as a ligature or otherwise). 

registered trademark

noun
  • A trademark that has been officially registered with the government by its owner. Indicated by the symbol ®. 

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