interrogation mark vs mix up

interrogation mark

noun
  • A question mark. 

mix up

noun
  • A confusion or reversal. 

  • A mix, blend, or variety. 

verb
  • To become involved with, especially socially or romantically. 

  • To confuse or reverse. 

  • To prepare something from ingredients that are mixed. 

  • To shuffle. 

  • To combine thoroughly. 

  • To mix or blend thoroughly and completely. 

How often have the words interrogation mark and mix up occurred in a corpus of books? (source: Google Ngram Viewer )