Google Panda refresh happening over the weekend. Google said that this refresh version 3.7 started rolling out on Friday, June 8th. This Panda reresh has an impact of less than 1% of search queries in the U.S. and about 1% worldwide, Google said in a tweet.
The last, time Google rolled out Panda Update version 3.6 was on April 27th.
FYI Panda data refresh started rolling out on Friday. Less than 1% of queries noticeably affected in the U.S. & 1% worldwide-- A Googler (@google) June 11, 2012