According to Hitwise the May 2010 U.S. search marketing share grew 1% from April and back up to 72% of share on search queries. Month on month change of Yahoo! Search, Bing and Ask is -3%, -2% and -2% respectively.
By Industry:
Google hasn’t been above 72% on the hitwise chart since last December. That time Google’s search market share was 72.25%.