New figures released by Nielsen Online so that all but 10% of Wikipedia’s traffic comes from search engines and other sites, and that most of that traffic comes from Google.

Referrals from Google make up 61% of all visitors to Wikipedia from homes, and 66% from work places. Yahoo delivers 19% and 16% respectively.

Wikipedia’s reliance on search traffic has been long known, but with Google Knol on the way (eventually) this year, any decision to down grade Wikipedia’s place in Google’s search results in favor of Knol could easily wipe out over half of the sites traffic overnight.