i vs x

i

character
  • The ninth letter of the English alphabet, called i and written in the Latin script. 

noun
  • The name of the Latin-script letter I/i. 

x

character
  • The twenty-fourth letter of the English alphabet, called ex and written in the Latin script. 

  • Forming gender-neutral or otherwise more inclusive versions of words, especially Spanish-derived words by replacing both the masculine -o and feminine -a. 

conj
  • Used between the names of two characters to denote a ship, particularly in anime, manga, and video games. 

  • Used in place of and in artist collaborations. 

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