co- vs en-

co-

prefix
  • to the same degree 

  • together; mutually; jointly 

  • partner or subordinate in an activity 

  • of the opposite, of the counterpart; dual 

en-

prefix
  • on, onto 

  • an intensifier 

  • caused 

  • in, into 

  • covered 

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