AC vs ac

AC

noun
  • Companion of the Order of Australia. 

name
  • Aceh, an autonomous province of Indonesia. 

  • Acre, a state of Brazil. 

phrase
  • as charged, as in: guilty as charged, usually a/c. 

ac

adj
  • ante cibum, before meals 

noun
  • account; money of account 

  • alicyclic 

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