Don’t be overly alarmed, Google still controls nearly 2/3 of search volume at 65%, but it has dropped from peaking last year, and Bing owned search, including Yahoo and soon to be AOL, are up to 34%, or 1/3 of search in general terms. Is Bing, and the relationships that they have formed with other outlets, beginning to finally chip away at Google as they have been trying for years. A year ago, Google was at 67.6% of search, so though the drop is small, it is a drop, which may signify something. Worth keeping an eye on things.
To take a deeper look at the numbers, you can go to ComScore.