According to comScore, Google Sites led the U.S. explicit core search market in May with 65.5 percent market share (up 0.1 percentage points), followed by Yahoo! Sites with 15.9 percent and Microsoft Sites with 14.1 percent. Ask Network accounted for 2.9 percent of explicit core searches, followed by AOL, Inc. with 1.5 percent.
Totally Google powered searches accounted for 67.8 percent of searches , while 26.5 percent of searches were powered by Bing. So its a flat month.