in common vs mutually

in common

prep
  • Shared with one or more others. 

  • Held in joint possession. 

  • Possessing similar or identical qualities. 

mutually

adv
  • in a shared manner; equally; affecting all parties the same way 

  • in the same way, each to the other; reciprocally 

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