The company's Bing search engine climbed to 9.43 per cent of the US market in July, up from 8.23 per cent last June.
When you add in the numbers from Yahoo after the two companies agreed a joint search and advertising deal, the portion grows to a shade over 20 per cent.
Google's dominance suffered slightly as a result, with the company's US market share slipping from 77.54 per cent to 78.48 per cent, and globally it slipped to 89.23 per cent in July from 89.80 per cent in June.
The deal with Yahoo will take time to complete, so the joint numbers are currently just for reference.
Steve Ballmer said on a conference call that the process will cost over $200 million (£118 million) and will likely be completed over the next two years.
However internet data company StatCounter, which released the results, does not think the statistics mean Google is in any real trouble:
"Bing continues to make slow but steady progress but the combined Yahoo figures suggest that the deal announced last week will have to demonstrate major future synergies if it is to make any dent in Google's dominance."
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Gareth has been part of the consumer technology world in a career spanning three decades. He started life as a staff writer on the fledgling TechRadar, and has grown with the site (primarily as phones, tablets and wearables editor) until becoming Global Editor in Chief in 2018. Gareth has written over 4,000 articles for TechRadar, has contributed expert insight to a number of other publications, chaired panels on zeitgeist technologies, presented at the Gadget Show Live as well as representing the brand on TV and radio for multiple channels including Sky, BBC, ITV and Al-Jazeera. Passionate about fitness, he can bore anyone rigid about stress management, sleep tracking, heart rate variance as well as bemoaning something about the latest iPhone, Galaxy or OLED TV.