What does the percentage mean when a community wiki answer is marked "2 revs, 2 users 67%"?
From the answers to the Meta Stack Exchange question
it is a crude approximation of the percentage of the post that was contributed by the user who has contributed the most to it. (This will be the user whose name appears in the footer to the post. Often it will be the user who created the post, but this is not necessarily the case.)