Google maintains lead with 65.9 percent of U.S. market share in December 2011, according to comScore.
Market leader Google's share remains unchanged.
Share of searches among top U.S. providers remains constant.
Microsoft and Yahoo gain slight market share.
Pair loses ground versus market leader Google, when measured by share of U.S. searches.
Another month of search share growth helps Bing eat away slowly at Google's lead.
Explicit core share of U.S. searches shows Microsoft's growth.
Yahoo's share of U.S. searches has fallen while Bing and Google grow.
Microsoft's Bing search engine grew its share of U.S. searches in November slightly as others fell.
Introduction of Instant Search boosts search giant's market share.
Yahoo is unseated as the No. 2 search provider after a year of steady declines.
Microsoft and Yahoo's combined search share drops over four percentage points under new measurement approach.
E-mail and instant messaging lost out to social networks, as users spent far more time on sites like Facebook and Twitter.
Company says alliance is more harmful to competition than proposed 2008 deal.

June 6, 2012
1:00pm ET / 10:00am PT