Google is still the world’s dominant search engine (just ask the EU), but in the U.S., Microsoft’s Bing is picking up some steam.

According to data from comScore(Opens in a new window), Bing finally topped 20 percent market share in March.

Google dropped 0.1 points from February, but kept its U.S market lead with 64.4 percent—three times that of Microsoft, which grew 0.3 points to 20.1 percent. Yahoo also dipped slightly to 12.7 percent, while Ask Network and AOL rounded out the top five with 1.8 percent and 1.1 percent, respectively.

Under a deal inked in 2009, Microsoft powers Yahoo’s search site on the desktop. Today, both companies announced(Opens in a new window) an update to that 10-year agreement that gives Yahoo a bit more control.

Going forward, Bing will continue to power the “majority” of Yahoo’s search results on desktop. But Yahoo will “have increased flexibility to enhance the search experience” on desktop or mobile, the company said.

“Our global partnership with Yahoo has benefited our shared customers over the past five years and I look forward to building on what we’ve already accomplished together,” Microsoft CEO Satya Nadella said in a statement.

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Originally, meanwhile, Yahoo managed the sales force for both companies’ search advertisers. Now, Microsoft will handle sales for ads delivered by Microsoft’s Bing Ads platform, while Yahoo will handle its own Gemini ads platform. The engineers from both platforms, however, will be integrated in a transition set to begin this summer.

“Over the past few months, Satya and I have worked closely together to establish a revised search agreement that allow us to enhance our user experience and innovate more in our search business,” Yahoo chief Marissa Mayer said. “This renewed agreement opens up significant opportunities in our partnership that I’m very excited to explore.”