ac- vs co-

ac-

prefix
  • oak. 

  • to or with. 

co-

prefix
  • to the same degree 

  • together; mutually; jointly 

  • partner or subordinate in an activity 

  • of the opposite, of the counterpart; dual 

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