The Experian Hitwise reports that Bing powered search comprised 28% of the searches for the month of July.
This analysis was done on the basis of clicks made by the users on one of the search results shown in the search engine.
In July, Yahoo had success rate of 81.36% i.e. more than 81.36% of users of Yahoo search click on a link in search results. Bing had a success rate of 80.04% and Google had 67.56%.
Hitwise Search Engine Analysis has a report of about 73 search engines and those all search engines account for 5.90 percent of U.S. searches.