A survey has found Google has increased its share of the US web search market to 47.4 per cent with a gain of 0.4 per cent during December, while number two ranked Yahoo! also edged higher.

Web audience measurement company comScore Networks said number three ranked Microsoft's share slid 0.5 per cent to 10.5 per cent of US web searches, while InterActiveCorp's Ask.com's share dipped 0.1 per cent to 5.4 per cent.

Google has gained share in 16 of the last 17 months in the US, the world's largest internet market, according to comScore data.

Yahoo!'s share of the market rose 0.3 per cent to 28.5 per cent in December over November, the survey found.

An estimated 6.7 billion searches were conducted by US web users in December, up one per cent from November.

The number of US web search queries has grown 30 per cent since December of 2005, comScore said. Consumers performed 3.2 billion searches on Google sites, while Yahoo! drew 1.9 billion searches.